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Sample records for batio3 thin films

  1. Pulsed Laser Deposition of BaTiO3 Thin Films on Different Substrates

    Directory of Open Access Journals (Sweden)

    Yaodong Yang

    2010-01-01

    Full Text Available We have studied the deposition of BaTiO3 (BTO thin films on various substrates. Three representative substrates were selected from different types of material systems: (i SrTiO3 single crystals as a typical oxide, (ii Si wafers as a semiconductor, and (iii Ni foils as a magnetostrictive metal. We have compared the ferroelectric properties of BTO thin films obtained by pulsed laser deposition on these diverse substrates.

  2. Spectroscopic study of Co-doped BaTiO3 thin films

    International Nuclear Information System (INIS)

    The results of obtaining and studying the BaTiO3 thin polycrystalline films with Co addition are presented. The presence of thr phase transition in these films at the temperature of 120 deg C is indicated. The constant of the electron-phonon interaction in these films is higher by value as compared to the barium titanates monocrystals both pure and with the Co addition. The luminescence spectra of films with 0.5 and 1 at. % Co have similar wave lengths of the irradiation maximum. The absorption band with the maximum frequency of 5000 cm-1 is observed in the near IR-area

  3. Effect of oxygen partial pressure and anneal temperature on BaTiO3 thin film crystal structure

    Science.gov (United States)

    Zhang, Jing; Sun, De-gui; Fu, Xiuhua; Liu, Dong-mei; Pan, Yong-gang; Yang, Fei

    2015-08-01

    BaTiO3 film is deposited on single crystal MgO substrate with pulsed laser deposition, and its crystal structure and surface roughness are characterized by X-ray diffraction instrument and atomic force microscope. BaTiO3 film crystal quality is analyzed under three different oxygen partial pressure and three different annealing temperatures. The result shows that when the oxygen partial pressure is 15Pa, crystal surface (001) and (002) diffraction peak of BaTiO3 thin films have higher intensity. It indicated that the film has a good c-axis orientation. When the annealing temperature is 800°C, the intensity of diffraction peak is the maximum, and peak shape is sharper. BaTiO3 crystal film is obtained with highly preferred orientation, and film density is improved. Thus the film has less surface roughness and good crystalline state.

  4. Imprint Control of BaTiO3 Thin Films via Chemically Induced Surface Polarization Pinning.

    Science.gov (United States)

    Lee, Hyungwoo; Kim, Tae Heon; Patzner, Jacob J; Lu, Haidong; Lee, Jung-Woo; Zhou, Hua; Chang, Wansoo; Mahanthappa, Mahesh K; Tsymbal, Evgeny Y; Gruverman, Alexei; Eom, Chang-Beom

    2016-04-13

    Surface-adsorbed polar molecules can significantly alter the ferroelectric properties of oxide thin films. Thus, fundamental understanding and controlling the effect of surface adsorbates are crucial for the implementation of ferroelectric thin film devices, such as ferroelectric tunnel junctions. Herein, we report an imprint control of BaTiO3 (BTO) thin films by chemically induced surface polarization pinning in the top few atomic layers of the water-exposed BTO films. Our studies based on synchrotron X-ray scattering and coherent Bragg rod analysis demonstrate that the chemically induced surface polarization is not switchable but reduces the polarization imprint and improves the bistability of ferroelectric phase in BTO tunnel junctions. We conclude that the chemical treatment of ferroelectric thin films with polar molecules may serve as a simple yet powerful strategy to enhance functional properties of ferroelectric tunnel junctions for their practical applications. PMID:26901570

  5. Excimer laser assisted re-oxidation of BaTiO3 thin films on Ni metal foils

    International Nuclear Information System (INIS)

    Excimer laser assisted re-oxidation for reduced, crystallized BaTiO3 thin films on Ni-foils was investigated. It was found that the BaTiO3 can be re-oxidized at an oxygen partial pressure of ∼50 mTorr and substrate temperature of 350 °C without forming a NiOx interface layer between the film and base metal foil. The dielectric permittivity of re-oxidized films was >1000 with loss tangent values <2% at 100 Hz, 30 mVrms excitation signal. Electron Energy Loss Spectroscopy indicated that BaTiO3 thin films can be re-oxidized to an oxygen stoichiometry close to ∼3 (e.g., stoichiometric). High resolution cross sectional transmission electron microscopy showed no evidence of NiOx formation between the BaTiO3 and the Ni foil upon excimer laser re-oxidation. Spectroscopic ellipsometry studies on laser re-oxidized [001]C and [111]C BaTiO3 single crystals indicate that the re-oxidation of BaTiO3 single crystals is augmented by photo-excitation of the ozone, as well as laser pulse induced temperature and local stress gradients

  6. The coexistence of ferroelectricity and ferromagnetism in Mn-doped BaTiO3 thin films

    Institute of Scientific and Technical Information of China (English)

    Ding Bin-Feng; Zhou Sheng-Qiang

    2011-01-01

    5-at% Mn-doped and undoped BaTiO3 thin films have been grown under different oxygen partial pressures by Pulsed Laser Deposition (PLD) on platinum-coated sapphire substrates.X-ray diffraction (XRD) measurements for all the thin films reveal a similar polycrystalline single-phase perovskite structure.Ferroelectricity is observed in the Mn-doped and undoped BaTiO3 thin films grown under relatively high oxygen partial pressure.Ferromagnetic coupling of the Mn dopant ions,on the other hand,is only seen in Mn-doped BaTiO3 thin films prepared under low oxygen partial pressure in a wide temperature range from 5 K to 300 K,and is attributed to the enhanced exchange coupling between Mn dopants and electrons at oxygen vacancies.Our results show that the leakage current is decreased with the doped Mn,but increases the dielectric loss and decreases the dielectric constant,and the ferroelectricity is impaired.To produce ferromagnetism,oxygen vacancies are necessary,which unfortunately increase the leakage current.This confirms that the mutual interplay between the ferroelectricity and ferromagnetism can be tuned by exchange coupling of the doped-Mn and oxygen vacancies in the BaTiO3 thin films.

  7. Excimer laser assisted re-oxidation of BaTiO3 thin films on Ni metal foils

    Science.gov (United States)

    Bharadwaja, S. S. N.; Rajashekhar, A.; Ko, S. W.; Qu, W.; Motyka, M.; Podraza, N.; Clark, T.; Randall, C. A.; Trolier-McKinstry, S.

    2016-01-01

    Excimer laser assisted re-oxidation for reduced, crystallized BaTiO3 thin films on Ni-foils was investigated. It was found that the BaTiO3 can be re-oxidized at an oxygen partial pressure of ˜50 mTorr and substrate temperature of 350 °C without forming a NiOx interface layer between the film and base metal foil. The dielectric permittivity of re-oxidized films was >1000 with loss tangent values oxygen stoichiometry close to ˜3 (e.g., stoichiometric). High resolution cross sectional transmission electron microscopy showed no evidence of NiOx formation between the BaTiO3 and the Ni foil upon excimer laser re-oxidation. Spectroscopic ellipsometry studies on laser re-oxidized [001]C and [111]C BaTiO3 single crystals indicate that the re-oxidation of BaTiO3 single crystals is augmented by photo-excitation of the ozone, as well as laser pulse induced temperature and local stress gradients.

  8. Performance analysis of resistive switching devices based on BaTiO3 thin films

    Science.gov (United States)

    Samardzic, Natasa; Kojic, Tijana; Vukmirovic, Jelena; Tripkovic, Djordjije; Bajac, Branimir; Srdic, Vladimir; Stojanovic, Goran

    2016-03-01

    Resitive switching devices, memristors, have recenty attracted much attention due to promising performances and potential applications in the field of logic and memory devices. Here, we present thin film BaTiO3 based memristor fabricated using ink-jet printing technique. Active material is a single layer barium titanate film with thickness of ̴100 nm, sandwitched between metal electodes. Printing parameters were optimized aiming to achieve stable drop flow and uniform printed layer. Current-voltage characteristics show typical memristive behavior with pinched hysteresis loop crossed at the origin, with marked differences between High Resistive State (HRS) and Low Resistive State (LRS). Obtained resistive states are stable during numerous switching processes. The device also shows unipolar switching effect for negative voltage impulses. Variable voltage impulse amplitudes leads to the shifting of the energy levels of electode contacts resulting in changing of the overall current through the device. Structural charcterization have been performed using XRD analysis and SEM micrography. High-temperature current-voltage measurements combined with transport parameter analysis using Hall efect measurement system (HMS 3000) and Impedance Analyzer AC measurements allows deeper insigth into conduction mechanism of ferroelectric memristors.

  9. The Structure of BaTiO3 and BaTiO3-YBa2Cu3O7-δ Thin Films Studied by X-Ray Triple-Axis Diffraction

    Science.gov (United States)

    Yu, W. X.; Cui, S. F.; Wu, L. S.; Mai, Z. H.; Li, C. L.; Cui, D. F.; Chen, Z. H.

    The structures of BaTiO3 thin films and BaTiO3/YBa2Cu3O7-δ bilayer films grown on SrTiO3 and LaAlO3 substrates, respectively by pulsed laser deposition, have been investigated by X-ray triple-axis diffraction. The orientation, the interface mismatch and strain status, and the in-plane and perpendicular lattice constants of the epilayers have been determined by reciprocal space map analysis. The results show that both the lattice constants and the structural imperfections of the BaTiO3 layers are relevant to the oxygen partial pressure. The a⊥/a‖ increases while the full width at half maximum (FWHM) of the rocking curves decreases with the decrease in the partial oxygen pressure.

  10. Structural characterization and dielectric properties of BaTiO3 thin films obtained by spin coating

    Directory of Open Access Journals (Sweden)

    Branimir Bajac

    2014-12-01

    Full Text Available Barium titanate thin films were prepared by spin coating deposition technique of an acetic precursor sol and sintered at 750, 900 and 1050 °C. Phase composition of the obtained thin films was characterized by X-ray diffraction and Raman spectroscopy. Their morphology was analysed by scanning electron microscopy and atomic force microscopy. Dielectric properties of thin films sintered at 750 and 900 °C were characterized by LCD device, where the influence of sintering temperature on dielectric permittivity and loss tangent was inspected. It was concluded that higher sintering temperature increases grain size and amount of tetragonal phase, hence higher relative permittivity was recorded. The almost constant relative permittivity in the measured frequency (800 Hz–0.5 MHz and temperature (25–200 °C ranges as well as low dielectric loss are very important for the application of BaTiO3 films in microelectronic devices.

  11. AES study on the chemical composition of ferroelectric BaTiO3 thin films RF sputter-deposited on silicon

    Science.gov (United States)

    Dharmadhikari, V. S.; Grannemann, W. W.

    1983-01-01

    AES depth profiling data are presented for thin films of BaTiO3 deposited on silicon by RF sputtering. By profiling the sputtered BaTiO3/silicon structures, it was possible to study the chemical composition and the interface characteristics of thin films deposited on silicon at different substrate temperatures. All the films showed that external surface layers were present, up to a few tens of angstroms thick, the chemical composition of which differed from that of the main layer. The main layer had stable composition, whereas the intermediate film-substrate interface consisted of reduced TiO(2-x) oxides. The thickness of this intermediate layer was a function of substrate temperature. All the films showed an excess of barium at the interface. These results are important in the context of ferroelectric phenomena observed in BaTiO3 thin films.

  12. Piezoelectric and Dielectric Properties of Multilayered BaTiO3/(Ba,Ca)TiO3/CaTiO3 Thin Films.

    Science.gov (United States)

    Zhu, Xiao Na; Gao, Ting Ting; Xu, Xing; Liang, Wei Zheng; Lin, Yuan; Chen, Chonglin; Chen, Xiang Ming

    2016-08-31

    Highly oriented multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films were fabricated on Nb-doped (001) SrTiO3 (Nb:STO) substrates by pulsed laser deposition. The configurations of multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films are designed with the thickness ratio of 1:1:1 and 2:1:1 and total thickness ∼300 nm. Microstructural characterization by X-ray diffraction indicates that the as-deposited thin films are highly c-axis oriented and large in-plane strain is determined in BaTiO3 and CaTiO3 layers. Piezoresponse force microscopy (PFM) studies reveal an intense in-plane polarization component, whereas the out-of-plane shows inferior phase contrast. The optimized combination is found to be the BaTiO3-(Ba0.85Ca0.15)TiO3-CaTiO3 structure with combination ratio 2:1:1, which displays the largest domain switching amplitude under DC electric field, the largest room-temperature dielectric constant ∼646, a small dielectric loss of 0.03, and the largest dielectric tunability of ∼50% at 400 kV/cm. These results suggest that the enhanced dielectric and tunability performance are greatly associated with the large in-plane polarization component and domain switching. PMID:27514235

  13. Effect of oxygen content on the dielectric and ferroelectric properties of laser-deposited BaTiO3 thin films

    Science.gov (United States)

    Li, C. L.; Chen, Z. H.; Zhou, Y. L.; Cui, D. F.

    2001-06-01

    BaTiO3 thin films were epitaxially grown on SrTiO3 (001) and LaNiO3/SrTiO3 substrates by pulsed laser deposition under different oxygen pressures. The oxygen content in the BaTiO3 films was determined using modified Rutherford backscattering. The structural characteristics of the films were analysed by x-ray diffraction θ/2θ scan, ϕ scan, and symmetric and asymmetric ω scans. The dielectric and ferroelectric properties of the films were measured by an impedance analyser and by a Sawyer-Tower circuit, respectively. It was found that the atomic ratio of O/Ba and Ti/Ba in the BaTiO3 films increases with oxygen pressure. The films fabricated in the intermediate oxygen pressure range of 2 to 10 Pa show the c-axis oriented tetragonal structure with a stoichiometry close to the ideal value. These films exhibit a relatively large dielectric constant, small dielectric loss and good ferroelectricity with a symmetric hysteresis loop. For growth at low oxygen pressure i.e. 0.1 Pa, the film with tetragonal c-axis orientation shows significant degradation in its dielectric properties. For a higher deposition oxygen pressure of 20 Pa, the film has tetragonal a-axis orientation and shows no ferroelectricity but has the largest dielectric constant.

  14. Effectiveness of BaTiO3 dielectric patches on YBa2Cu3O7 thin films for MEM switches

    Science.gov (United States)

    Vargas, J.; Hijazi, Y.; Noel, J.; Vlasov, Y.; Larkins, G.

    2014-05-01

    A micro-electro-mechanical (MEM) switch built on a superconducting microstrip filter will be utilized to investigate BaTiO3 dielectric patches for functional switching points of contact. Actuation voltage resulting from the MEM switch provokes static friction between the bridge membrane and BaTiO3 insulation layer. The dielectric patch crystal structure and roughness affect the ability of repetitively switching cycles and lifetime. A series of experiments have been performed using different deposition methods and RF magnetron sputtering was found to be the best deposition process for the BaTiO3 layer. The effect examination of surface morphology will be presented using characterization techniques as x-ray diffraction, SEM and AFM for an optimum switching device. The thin film is made of YBa2Cu3O7 deposited on LaAlO3 substrate by pulsed laser deposition. For this work, the dielectric material sputtering pressure is set at 9.5×10-6 Torr. The argon gas is released through a mass-flow controller to purge the system prior to deposition. RF power is 85 W at a distance of 9 cm. The behavior of Au membranes built on ultimate BaTiO3 patches will be shown as part of the results. These novel surface patterns will in turn be used in modelling other RF MEM switch devices such as distributed-satellite communication system operating at cryogenic temperatures.

  15. Comprehensive dielectric performance of bismuth acceptor doped BaTiO3 based nanocrystal thin film capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, SY; Zhang, HN; Sviridov, L; Huang, LM; Liu, XH; Samson, J; Akins, D; Li, J; O' Brien, S

    2012-11-07

    We present a novel approach to preparing bismuth acceptor doped barium titanate nanocrystal formulations that can be deposited in conjunction with polymers in order to prepare a thin film nanocomposite dielectric that exhibits desirable capacitor characteristics. Exploring the limits of dielectric function in nanocomposites is an important avenue of materials research, while paying strict attention to the overall device quality, namely permittivity, loss and equivalent series resistance (ESR). Pushing capacitor function to higher frequencies, a desirable goal from an electrical engineering point of view, presents a new set of challenges in terms of minimizing interfacial, space charge and polarization effects within the dielectric. We show the ability to synthesize BaTi0.96Bi0.04O3 or BaTi0.97Bi0.03O3 depending on nominal molar concentrations of bismuth at the onset. The low temperature solvothermal route allows for substitution at the titanium site (strongly supported by Rietveld and Raman analysis). Characterization is performed by XRD with Rietveld refinement, Raman Spectroscopy, SEM and HRTEM. A mechanism is proposed for bismuth acceptor substitution, based on the chemical reaction of the alkoxy-metal precursors involving nucleophilic addition. Dielectric analysis of the nanocrystal thin films is performed by preparing nanocrystal/PVP 2-2 nanocomposites (no annealing) and comparing BaTi0.96Bi0.04O3 and BaTi0.97Bi0.03O3 with undoped BaTiO3. Improvements of up to 25% in capacitance (permittivity) are observed, with lower loss and dramatically improved ESR, all to very high frequency ranges (>10 MHz).

  16. Effect of crystal orientation on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO3 thin films

    International Nuclear Information System (INIS)

    The influence of crystal orientations on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO3 thin films has been investigated using an expanded nonlinear thermodynamic theory. The calculations reveal that crystal orientation has significant influence on the phase stability and phase transitions in the misfit strain-temperature phase diagrams. In particular, the (110) orientation leads to a lower symmetry and more complicated phase transition than the (111) orientation in BaTiO3 films. The increase of compressive strain will dramatically enhance the Curie temperature TC of (110)-oriented BaTiO3 films, which matches well with previous experimental data. The polarization components experience a great change across the boundaries of different phases at room temperature in both (110)- and (111)-oriented films, which leads to the huge dielectric and piezoelectric responses. A good agreement is found between the present thermodynamics calculation and previous first-principles calculations. Our work provides an insight into how to use crystal orientation, epitaxial strain and temperature to tune the structure and properties of ferroelectrics

  17. Oxygen vacancy induced magnetism in BaTiO3-δ and Nb:BaTiO3-δ thin films

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The unusual magnetic properties are observed in oxygen deficient BaTiO3-δ(BTO) and Nb:BaTiO3-δ(BNTO) thin films fabricated on SrTiO3 substrates by laser molecular beam epitaxy.The distinct magnetic hysteresis loops are observed in the oxygen deficient BTO and BNTO thin films in a temperature range of 5 to 300 K,whereas the diamagnetism is observed in both BTO and BNTO annealed at 1 atm of oxygen.The dopant Nb only enhances the magnetization in BNTO thin films,but has little effect on the coercivity.The magnetism of BTO and BNTO films is proposed to be the oxygen vacancies by origin.

  18. Studies on resistive hysteresis characteristics of metal organic decomposition-derived BaTiO3 thin films prepared under various annealing conditions and related switching endurance properties

    Science.gov (United States)

    Sugie, Toshiyuki; Maejima, So; Yamashita, Kaoru; Noda, Minoru

    2016-10-01

    We have prepared metal organic decomposition (MOD)-derived BaTiO3 (BT) thin films under various annealing conditions, especially in nitrogen, and investigated the properties of bipolar-type resistive switching, focusing on the relation between oxygen vacancies and the behavior of resistive hysteresis. BT thin film with both pre annealing and final annealing in nitrogen (layer-by-layer annealing) showed the resistive hysteresis of bipolar-type switching with current ON/OFF ratios of 2 orders of magnitude for both bias polarities. Moreover, it showed the endurance property with the 104 switching cycles. It is possible that the non-filament bipolar-type resistive switching has origins not only at the metal electrode/oxide interface but also the inside of the oxide films, that is, the presence of the oxygen vacancies inside of BT thin films would play an important role in the bipolar-type resistive switching and in improving the switching endurance properties.

  19. Ferroelectric polarization and resistive switching characteristics of ion beam assisted sputter deposited BaTiO3 thin films

    Science.gov (United States)

    Silva, J. P. B.; Kamakshi, Koppole; Sekhar, K. C.; Moreira, J. Agostinho; Almeida, A.; Pereira, M.; Gomes, M. J. M.

    2016-05-01

    In this work, 150 nm thick polycrystalline BaTiO3 (BTO) films were deposited on Pt/TiO2/SiO2/Si substrate by ion beam assisted sputter deposition technique. The bias voltage dependent resistive switching (RS) and ferroelectric polarization characteristics of Au/BTO/Pt devices are investigated. The devices display the stable bipolar RS characteristics without an initial electroforming process. Fittings to current-voltage (I-V) curves suggest that low and high resistance states are governed, respectively, by filamentary model and trap controlled space charge limited conduction mechanism, where the oxygen vacancies act as traps. Presence of oxygen vacancies is evidenced from the photoluminescence spectrum. The devices also display P-V loops with remnant polarization (Pr) of 5.7 μC/cm2 and a coercive electric field (Ec) of 173.0 kV/cm. The coupling between the ferroelectric polarization and RS effect in BTO films is demonstrated.

  20. Structural characterisation of BaTiO3 thin films deposited on SrRuO3/YSZ buffered silicon substrates and silicon microcantilevers

    OpenAIRE

    Colder, Héloïse; Domengès, B.; Jorel, Corentin; Marie, P.; Boisserie, M.; Guillon, Samuel; Nicu, Liviu; Galdi, Alice; Mechin, Laurence

    2014-01-01

    We report on the progress towards an all epitaxial oxide layer technology on silicon substrates for epitaxial piezoelectric microelectromechanical systems. (101)-oriented epitaxial tetragonal BaTiO3 (BTO) thin films were deposited at two different oxygen pressures, 5.10 2 mbar and 5.10 3 mbar, on SrRuO3/Yttria-stabilized zirconia (YSZ) buffered silicon substrates by pulsed laser deposition. The YSZ layer full (001) orientation allowed the further growth of a fully (110)-oriented conductive Sr...

  1. Layer by layer growth of BaTiO 3 thin films with extremely smooth surfaces by laser molecular beam epitaxy

    Science.gov (United States)

    Wang, H. S.; Ma, K.; Cui, D. F.; Peng, Z. Q.; Zhou, Y. L.; Lu, H. B.; Chen, Z. H.; Li, L.; Yang, G. Z.

    1997-05-01

    Using pure ozone-assisted laser molecular beam epitaxy, we have grown c-axis-oriented single crystal BaTiO 3 thin films on SrTiO 3 substrates at temperatures ( Ts) of 400-750°C and under ambient gas pressures of 5 × 10 -5 to 1 × 10 -1 Pa, respectively. Stripy reflection high-energy electron diffraction (RHEED) patterns and regular RHEED intensity oscillations reveal the smooth surface and layer-by-layer epitaxial growth of the films. Scanning electron microscopy analysis shows that the films are free of pinholes, grain boundaries and outgrowths on the surface. In addition, we found a strong dependence of the film lattice constant c on Ts, which might be related to the strain in the film.

  2. Structure,Electrical,and Optical Properties of Nb-doped BaTiO3 Thin Films Grown by Laser Molecular Beam Epitaxy

    Institute of Scientific and Technical Information of China (English)

    GUO Hai-Zhong; LIU Li-Feng; LU Hui-Bin; FEI Yi-Yan; XIANG Wen-Feng; ZHOU Yue-Liang; CHEN Zheng-Hao

    2004-01-01

    @@ Structure, electrical, and optical properties of Nb-doped BaTiO3 (Nb:BTO) thin films on MgO substrates grown by laser molecular beam epitaxy with increasing Nb content were investigated. The Nb:BTO thin films with high crystallinity are epitaxially grown on MgO substrates. With more Nb-doped content, the impurity phases are found in Nb:BTO thin films. Hall measurement at room temperature confirms that the charge carriers of the Nb:BTO thin films are n-type. When the Nb-doped content increases, the carrier concentration and carrier mobility increase. Meanwhile the optical transmittance decreases with the increase of the Nb-doping, and the width of the forbidden band in each group is not affected by the presence of Nb in the samples. Raman spectra show that the structural phase transition may occur with the increase of the Nb-doping content, in the meantime more defects and impurities exist in the Nb:BTO thin films.

  3. Crystal structure and polarization hysteresis properties of ferroelectric BaTiO3 thin-film capacitors on (Ba,Sr)TiO3-buffered substrates

    Science.gov (United States)

    Maki, Hisashi; Noguchi, Yuji; Kutsuna, Kazutoshi; Matsuo, Hiroki; Kitanaka, Yuuki; Miyayama, Masaru

    2016-10-01

    Ferroelectric BaTiO3 (BT) thin-film capacitors with a buffer layer of (Ba1- x Sr x )TiO3 (BST) have been fabricated on (001) SrTiO3 (STO) single-crystal substrates by a pulsed laser deposition method, and the crystal structure and polarization hysteresis properties have been investigated. X-ray diffraction reciprocal space mapping shows that the BST buffer effectively reduces the misfit strain relaxation of the BT films on SrRuO3 (SRO) electrodes. The BT capacitor with the SRO electrodes on the BST (x = 0.3) buffer exhibits a well-saturated hysteresis loop with a remanent polarization of 29 µC/cm2. The hysteresis loop displays a shift toward a specific field direction, which is suggested to stem from the flexoelectric coupling between the out-of-plane polarization and the strain gradient adjacent to the bottom interface.

  4. Structural, dielectric and electromechanical study of Hf-substituted BaTiO3 thin films fabricated by CSD

    International Nuclear Information System (INIS)

    Hafnium-substituted barium titanate thin films were deposited on platinized silicon substrates. Two different concentrations of solutions (0.1 M and 0.3 M) were used to deposit films of various compositions Ba(Ti1-x,Hfx)O3 (x=0.03, 0.05, 0.07, 0.1, 0.2, 0.3 and 0.4). The microstructure of the films depended on the concentration of the solution. Lower concentration (0.1 M) solutions led to columnar films, but with higher hafnium percent compositions the columnar structure was lost. The films which were derived from the 0.1 M concentration solutions had better dielectric and electrical properties compared to the films derived from a higher concentration (0.3 M). All the films were found to be polycrystalline in nature. The dielectric constant of the films was found to decrease with higher amounts of hafnium substitution. From the I-V characteristics it is noticed that the leakage decreases by almost four orders of magnitude with a hafnium substitution of 40%. The d33 values of the films were between 23 and 5.6 pm/V for the different films. (orig.)

  5. Structural characterisation of BaTiO3 thin films deposited on SrRuO3/YSZ buffered silicon substrates and silicon microcantilevers

    International Nuclear Information System (INIS)

    We report on the progress towards an all epitaxial oxide layer technology on silicon substrates for epitaxial piezoelectric microelectromechanical systems. (101)-oriented epitaxial tetragonal BaTiO3 (BTO) thin films were deposited at two different oxygen pressures, 5.10−2 mbar and 5.10−3 mbar, on SrRuO3/Yttria-stabilized zirconia (YSZ) buffered silicon substrates by pulsed laser deposition. The YSZ layer full (001) orientation allowed the further growth of a fully (110)-oriented conductive SrRuO3 electrode as shown by X-ray diffraction. The tetragonal structure of the BTO films, which is a prerequisite for the piezoelectric effect, was identified by Raman spectroscopy. In the BTO film deposited at 5.10−2 mbar strain was mostly localized inside the BTO grains whereas at 5.10−3 mbar, it was localized at the grain boundaries. The BTO/SRO/YSZ layers were finally deposited on Si microcantilevers at an O2 pressure of 5.10−3 mbar. The strain level was low enough to evaluate the BTO Young modulus. Transmission electron microscopy (TEM) was used to investigate the epitaxial quality of the layers and their epitaxial relationship on plain silicon wafers as well as on released microcantilevers, thanks to Focused-Ion-Beam TEM lamella preparation

  6. Polarization switching dynamics in thin-film BaTiO3/PbZr0.2Ti0.8O3 bilayer capacitors

    Science.gov (United States)

    Salev, Pavel; Grigoriev, Alexei

    2013-03-01

    In this work, we compare polarization switching and dielectric properties of single- (PbZr0.2Ti0.8O3 (PZT)) and bi-layer (BaTiO3/PbZr0.2Ti0.8O3 (BTO/PZT)) ferroelectric thin-film materials. The ferroelectric films were grown by radio-frequency magnetron sputtering on SrRuO3/SrTiO3 (001) substrates. Pt top electrodes ranging in diameter from 50 um to 200 um were fabricated on top of ferroelectric films. Electrical measurements of switching dynamics and dielectric response revealed a significant difference in polarization switching between single- and bi-layer capacitors. Average remnant polarization in the bilayer was reduced to 60 uC/cm2 from 90 uC/cm2 polarization in a single layer capacitor, and the switching speed was reduced significantly. In this presentation, we will discuss effects of interfaces and polarization coupling on polarization dynamics and on the dielectric response in ferroelectric multilayers.

  7. Vacancy-induced magnetism in BaTiO3(001) thin films based on density functional theory.

    Science.gov (United States)

    Cao, Dan; Cai, Meng-Qiu; Hu, Wang-Yu; Yu, Ping; Huang, Hai-Tao

    2011-03-14

    The origin of magnetism induced by vacancies on BaTiO(3)(001) surfaces is investigated systematically by first-principles calculations within density-functional theory. The calculated results show that O vacancy is responsible for the magnetism of the BaO-terminated surface and the magnetism of the TiO(2)-terminated surface is induced by Ti vacancy. For the BaO-terminated surface, the magnetism mainly arises from the unpaired electrons that are localized in the O vacancy basin. In contrast, for the TiO(2)-terminated surface, the magnetism mainly originates from the partially occupied O-2p states of the first nearest neighbor O atoms surrounding the Ti vacancy. These results suggest the possibility of implementing magneto-electric coupling in conventional ferroelectric materials.

  8. Dielectric Enhancement and Maxwell-Wagner Effect in Polycrystalline BaTiO3/Ba0.2Sr0.8TiO3 Multilayered Thin Films

    Institute of Scientific and Technical Information of China (English)

    葛水兵; 沈明荣; 宁兆元

    2002-01-01

    Polycrystalline BaTiO3/Ba0.2Sr0.sTiO3 multilayer thin films were fabricated by pulsed laser deposition onto Pt/Ti/SiO2/Si substrates with various stacking periodicities. The dielectric constant of the films was obviously enhanced with the decrease of the individual layer thickness, while the dielectric loss was kept at a low level comparable to that of the pure Ba0.6Sr0.4TiO3 thin films. The Maxwell-Wagner model is used to explain the experimental data.

  9. Stress effect on Raman spectra of Ce-doped BaTiO3 films

    Science.gov (United States)

    Chen, M. S.; Shen, Z. X.; Tang, S. H.; Shi, W. S.; Cui, D. F.; Chen, Z. H.

    2000-08-01

    Ce-doped BaTiO3 (BTO:Ce) thin films prepared on MgO (100) substrates by pulsed laser deposition (PLD) at oxygen pressure of 1.2×10-3 and 17 Pa have been studied by micro-Raman spectroscopy, x-ray diffraction (XRD) and atomic force microscopy (AFM). The film deposited at lower oxygen pressure has a larger lattice parameter in the direction normal to the substrate surface, and the film has smaller grains and a smoother surface. The polarized Raman peaks of both as-deposited films show blue shifts and linewidth broadening in comparison to those of the BaTiO3 single crystal. The blue shifts are attributed to tensile stresses in the films. Our results indicate that the grain size increases and the tensile stress relaxes with annealing. We have shown that quantum confinement and oxygen vacancies are not the dominant factors for the observed Raman spectral changes.

  10. Enhancement of ferroelectric Curie temperature in BaTiO3 films via strain-induced defect dipole alignment.

    Science.gov (United States)

    Damodaran, Anoop R; Breckenfeld, Eric; Chen, Zuhuang; Lee, Sungki; Martin, Lane W

    2014-09-01

    The combination of epitaxial strain and defect engineering facilitates the tuning of the transition temperature of BaTiO3 to >800 °C. Advances in thin-film deposition enable the utilization of both the electric and elastic dipoles of defects to extend the epitaxial strain to new levels, inducing unprecedented functionality and temperature stability in ferroelectrics. PMID:25099557

  11. BaTiO3和SrTiO3薄膜生长初期化学分子反应机理%Reaction mechanism of chemical molecules in early growth of BaTiO3 and SrTiO3 thin films

    Institute of Scientific and Technical Information of China (English)

    梁晓琴; 张姝; 黄平; 杨春

    2012-01-01

    Density functional theory(DFT) is applied to study microscopic reaction mechanism of the formation of BaTiO3 and Sr-TiOjby BaO,SrO and TiO2 molecules and Ti2O3by two TiO2 molecules. The reaction intermediates,transition states and activation energies have been obtained. NBO is used to analyze bonding process,orbital interactions and atomic charges in intermediates and transition states of the reaction process. The calculated results show activation energies of the formation of BaTiO3 ,SrTiO,and Ti2O4 are respectively 16.3,17. 3 and 9.6 kJ/moL Activation energies of Ti2O4 is relatively lower ,TiO2 dimer observed in the experiment can theoretically be explained. However,the reaction enthalpies of the formation of the first intermediates of BaTiO3 and SrTiO3 are respectively-484.7 and-534.7 kj/mol. Activation energies are low. And strong orbital interactions and static gravitations are found in molecules. These results indicate that BaO and SrO acts as a combining center TiO2in the early growth of BaTiO3and SrTiO3thin films,which should be propitious to form of primary unit cell.%本文采用B3LYP密度泛函方法,研究了BaO、SrO与TiO2形成BaTiO3、SrTiO3及TiO2二聚形成Ti2O4的微观反应机理,获得了相应的中间体、过渡态及反应活化能.采用自然键轨道NBO方法分析了反应过程中各中间体和过渡态的成键情况、轨道间的相互作用以及原子的电荷.计算结果表明,形成BaTiO3、SrTiO3和Ti2O4反应活化能分别为16.3、17.3和9.6 kJ/mol,TiO2形成二聚体活化能相对较小,从理论上解释了实验过程中观测到TiO2二聚体;但SrO、BaO和TiO2形成BaTiO3、SrTiO3的反应过程中,形成最初的稳定中间体时分别放热484.7和534.7 kJ/mol,且活化能较低,轨道间相互作用较强,静电引力作用显著,有利于SrTiO3和BaTiO3薄膜生长初期以TiO2为中心,结合BaO和SrO成核生长,从而有利予单元胞的进一步形成.

  12. Preparation and Basic Properties of BaTiO3-BaPbO3 Multilayer Thin Films by Metal-Alkoxides Method

    Science.gov (United States)

    Azuma, Takahiro; Takahashi, Sheiji; Kuwabara, Makoto

    1993-09-01

    Preferentially oriented barium titanate (BTO)-barium metaplumbate (BPO) multilayer thin films were prepared by the metal-alkoxides method on MgO single crystals. The BPO layer is an electrode for the BTO layer. Thin films were deposited on cleaved MgO (100) substrates by spin coating. A BTO film of 0.4 μm thickness on the BPO layer shows a dielectric constant of about 400 at room temperature. No formation of reaction phases between BTO and BPO, fired at 800°C to yield a well-crystallized BTO film, was detected in X-ray diffraction analysis.

  13. Single-crystalline BaTiO3 films grown by gas-source molecular beam epitaxy

    Science.gov (United States)

    Matsubara, Yuya; Takahashi, Kei S.; Tokura, Yoshinori; Kawasaki, Masashi

    2014-12-01

    Thin BaTiO3 films were grown on GdScO3 (110) substrates by metalorganic gas-source molecular beam epitaxy. Titanium tetra-isopropoxide (TTIP) was used as a volatile precursor that provides a wide growth window of the supplied TTIP/Ba ratio for automatic adjustment of the film composition. Within the growth window, compressively strained films can be grown with excellent crystalline quality, whereas films grown outside of the growth window are relaxed with inferior crystallinity. This growth method will provide a way to study the intrinsic properties of ferroelectric BaTiO3 films and their heterostructures by precise control of the stoichiometry, structure, and purity.

  14. Conformal BaTiO3 Films with High Piezoelectric Coupling through an Optimized Hydrothermal Synthesis.

    Science.gov (United States)

    Zhou, Zhi; Bowland, Christopher C; Patterson, Brendan A; Malakooti, Mohammad H; Sodano, Henry A

    2016-08-24

    Two-dimensional (2D) ferroelectric films have vast applications due to their dielectric, ferroelectric, and piezoelectric properties that meet the requirements of sensors, nonvolatile ferroelectric random access memory (NVFeRAM) devices, and micro-electromechanical systems (MEMS). However, the small surface area of these 2D ferroelectric films has limited their ability to achieve higher memory storage density in NVFeRAM devices and more sensitive sensors and transducer. Thus, conformally deposited ferroelectric films have been actively studied for these applications in order to create three-dimensional (3D) structures, which lead to a larger surface area. Most of the current methods developed for the conformal deposition of ferroelectric films, such as metal-organic chemical vapor deposition (MOCVD) and plasma-enhanced vapor deposition (PECVD), are limited by high temperatures and unstable and toxic organic precursors. In this paper, an innovative fabrication method for barium titanate (BaTiO3) textured films with 3D architectures is introduced to alleviate these issues. This fabrication method is based on converting conformally grown rutile TiO2 nanowire arrays into BaTiO3 textured films using a simple two-step hydrothermal process which allows for thickness-controlled growth of conformal films on patterned silicon wafers coated with fluorine-doped tin oxide (FTO). Moreover, the processing parameters have been optimized to achieve a high piezoelectric coupling coefficient of 100 pm/V. This high piezoelectric response along with high relative dielectric constant (εr = 1600) of the conformally grown textured BaTiO3 films demonstrates their potential application in sensors, NVFeRAM, and MEMS. PMID:27487556

  15. Conformal BaTiO3 Films with High Piezoelectric Coupling through an Optimized Hydrothermal Synthesis.

    Science.gov (United States)

    Zhou, Zhi; Bowland, Christopher C; Patterson, Brendan A; Malakooti, Mohammad H; Sodano, Henry A

    2016-08-24

    Two-dimensional (2D) ferroelectric films have vast applications due to their dielectric, ferroelectric, and piezoelectric properties that meet the requirements of sensors, nonvolatile ferroelectric random access memory (NVFeRAM) devices, and micro-electromechanical systems (MEMS). However, the small surface area of these 2D ferroelectric films has limited their ability to achieve higher memory storage density in NVFeRAM devices and more sensitive sensors and transducer. Thus, conformally deposited ferroelectric films have been actively studied for these applications in order to create three-dimensional (3D) structures, which lead to a larger surface area. Most of the current methods developed for the conformal deposition of ferroelectric films, such as metal-organic chemical vapor deposition (MOCVD) and plasma-enhanced vapor deposition (PECVD), are limited by high temperatures and unstable and toxic organic precursors. In this paper, an innovative fabrication method for barium titanate (BaTiO3) textured films with 3D architectures is introduced to alleviate these issues. This fabrication method is based on converting conformally grown rutile TiO2 nanowire arrays into BaTiO3 textured films using a simple two-step hydrothermal process which allows for thickness-controlled growth of conformal films on patterned silicon wafers coated with fluorine-doped tin oxide (FTO). Moreover, the processing parameters have been optimized to achieve a high piezoelectric coupling coefficient of 100 pm/V. This high piezoelectric response along with high relative dielectric constant (εr = 1600) of the conformally grown textured BaTiO3 films demonstrates their potential application in sensors, NVFeRAM, and MEMS.

  16. Synthesis of tetragonal BaTiO3 film on Ti substrate by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    PENG Ji-hua; LI Wen-fang; HAN Bing; HUANG Fang-liang; DU Jun

    2008-01-01

    BaTiO3 films on Ti substrate were fabricated by alternative current(AC) and direct current(DC) micro arc oxidation (MAO). Microstructures of films were investigated by means of SEM, XRD and TEM. The results show that the amorphous phase and primitive cubic phase are the main phases in the films prepared by AC MAO. Even after being annealed at 1 200 ℃ for 8 h,only a few tetragonal phases can be observed in films prepared by AC MAO. However, tetragonal BaTiO3 phase can be produced by DC MAO directly. In the films prepared by DC MAO, a mixture of cubic phase and tetragonal phase is formed. After sparking spacious distribution, sparking duration and temperature gradient near sparking sites were taken into account, and a mechanism of synthesis of tetragonal BaTiO3 phase by DC MAO was proposed.

  17. Domain evolution of BaTiO3 ultrathin films under electric field: a first-principles study

    OpenAIRE

    Lai, Bo-Kuai; Ponomareva, Inna; Kornev, Igor A.; Bellaiche, L.; Salamo, G. J.

    2006-01-01

    A first-principles-derived method is used to study the morphology and electric-field-induced evolution of stripe nanodomains in (001) BaTiO3 (BTO) ultrathin films, and to compare them with those in (001) Pb(Zr,Ti)O3 (PZT) ultrathin films. The BaTiO3 systems exhibit 180o periodic stripe domains at null electric field, as in PZT ultrathin films. However, the stripes alternate along [1-10] in BTO systems versus [010] in PZT systems, and no in-plane surface dipoles occur in BTO ultrathin films (u...

  18. The structural properties of BaTiO3: TiO2: PMMA composite films at room temperature

    Science.gov (United States)

    Dey, Subhrangsu; Singh, S.; Singh, S. M.; Rajput, Nikhil; Kumar, Neeraj

    2016-05-01

    Present works based on the performance of the composite films of Barium Titanate (BaTiO3) with Titanium Dioxide (TiO2) and Poly (methyl methacrylate) (PMMA) prepared by simple solution casting technique. Different wt. % compositions of BaTiO3 have been selected to find out the best optimized condition for further investigations. The structural properties have been carried out at room temperature using X-ray crystallography (XRD). The average crystallite size of the BaTiO3 particles in the composite films has been found to be lies in between ˜ 20 -70 nm. It has been found that the peak intensities increase with increasing the wt. % of BaTiO3 in the composite films at room temperature (RT). The XRD analysis revealed that the addition of TiO2 has played a crucial role to enhance the crystalline nature of the composite films at room temperature. Efforts have been made to correlate the results with investigated XRD results of pure BaTiO3 and its composites as observed by other workers at room temperature.

  19. Study of electronic and magnetic properties and related x-ray absorption spectroscopy of ultrathin Co films on BaTiO3

    International Nuclear Information System (INIS)

    We present a first-principles study of electronic and magnetic properties of thin Co films on a BaTiO3(0 0 1) single crystal. The crystalline structure of 1–3 monolayer thick Co films was determined and served as input for calculations of the electronic and magnetic properties of the films. The estimation of exchange constants indicates that the Co films are ferromagnetic with a high critical temperature, which depends on the film thickness and the interface geometry. In addition, we calculated x-ray absorption spectra, related magnetic circular dichroism (XMCD) and linear dichroism (XLD) of the Co L 2, 3 edges as a function of Co film thickness and ferroelectric polarization of BaTiO3. We found characteristic features, which depend strongly on the magnetic properties and the structure of the film. While there is only a weak dependence of XMCD spectra on the ferroelectric polarization, the XLD of the films is much more sensitive to the polarization switching, which could possibly be observed experimentally. (paper)

  20. Dielectric strength of voidless BaTiO3 films with nano-scale grains fabricated by aerosol deposition

    International Nuclear Information System (INIS)

    In order to investigate the dielectric strength properties of the BaTiO3 films with nano-scale grains with uniform grain size and no voids, BaTiO3 films were fabricated with a thickness of 1 μm by an AD process, and the fabricated films were sintered at 800, 900, and 1000 °C in air and reducing atmosphere. The films have superior dielectric strength properties due to their uniform grain size and high density without any voids. In addition, based on investigation of the leakage current (intrinsic) properties, it was confirmed that the sintering conditions of the reducing atmosphere largely increase leakage currents due to generated electrons and doubly ionized oxygen vacancies following the Poole-Frenkel emission mechanism, and increased leakage currents flow at grain boundary regions. Therefore, we conclude that the extrinsic breakdown factors should be eliminated for superior dielectric strength properties, and it is important to enhance grain boundaries by doping acceptors and rare-earth elements

  1. A first-principles study of phase transitions in ultrathin films of BaTiO3

    Indian Academy of Sciences (India)

    J Paul; T Nishimatsu; Y Kawazoe; U V Waghmare

    2008-02-01

    We determine the effects of film thickness, epitaxial strain and the nature of electrodes on ferroelectric phase transitions in ultrathin films of BaTiO3 using a first-principles effective Hamiltonian in classical molecular dynamics simulations. We present results for polarization and dielectric properties as a function of temperature and epitaxial strain, leading to size-dependent temperature-strain phase diagram for the films sandwiched between `perfect' electrodes. In the presence of non-vanishing depolarization fields when non-ideal electrodes are used, we show that a stable stripe-domain phase is obtained at low temperatures. The electrostatic images in the presence of electrodes and their interaction with local dipoles in the film explain these observed phenomena.

  2. Laser Molecular Beam Epitaxy Growth of BaTiO3 in Seven Thousands of Unit-Cell Layers

    Institute of Scientific and Technical Information of China (English)

    HUANG Yan-Hong; YANG Guo-Zhen; HE Meng; ZHAO Kun; TIAN Huan-Fang; L(U) Hui-Bin; JIN Kui-Juan; CHEN Zheng-Hao; ZHOU Yue-Liang; LI Jian-Qi

    2005-01-01

    @@ BaTiO3 thin films in seven thousands of unit-cell layers have been successfully fabricated on SrTiO3 (001)substrates by laser molecular beam epitaxy. The fine streak pattern and the undamping intensity oscillation of reflection high-energy electron diffraction indicate that the BaTiO3 film was layer-by-layer epitaxial growth. The measurements of scanning electron microscopy and atomic force microscopy show that surfaces of the BaTiO3thin film are atomically smooth. The measurements of x-ray diffraction and transmission electron microscopy,as well as selected-area electron diffraction revealthat the BaTiO3 thin film is a c-oriented epitaxial crystalline structure.

  3. Effects of substrate materials on piezoelectric properties of BaTiO3 thick films deposited by aerosol deposition

    Science.gov (United States)

    Kawakami, Yoshihiro; Watanabe, Masato; Arai, Ken-Ichi; Sugimoto, Satoshi

    2016-10-01

    Piezoelectric properties were evaluated for annealed BaTiO3 (BT) films formed by aerosol deposition on yttria-stabilized zirconia (YSZ) and Fe-Cr-Al-based heat-resistant stainless steel (SS). The piezoelectric constants d 31 of BT films annealed at 1200 °C formed on YSZ and SS were -71 and -41 pm/V, respectively. The effects of different substrates on piezoelectric properties were investigated. The grain sizes of the films formed on YSZ and SS were 1.5 and 1.0 µm, respectively. X-ray diffraction analysis using a two-dimensional stress method revealed that the respective residual stresses of the films formed on YSZ and SS were -55 ± 8 and -32 ± 7 MPa, respectively, as compressive stresses. The c-domain structure was formed preferentially in the films on SS because of its larger compressive stress. These results suggest that differences in piezoelectric properties attributable to substrates result from differences in compressive stress magnitude and the volume fraction between the c- and a-domains.

  4. Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO 3 nanoparticles for energy storage applications

    KAUST Repository

    Almadhoun, Mahmoud Nassar Mahmoud

    2012-01-01

    A facile surface hydroxylation treatment using hydrogen peroxide to modify the surface of BaTiO 3 nanofillers dispersed in a ferroelectric copolymer host has been investigated. We demonstrate that the surface functionalization of the BaTiO 3 nanofillers (<100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity and breakdown strength of the thin-film nanocomposites. Surface modified BaTiO 3 particles display better dispersion within the polymer matrix, resulting in enhanced relative permittivity and reduced dielectric loss. The dielectric behavior of the nanocomposite films containing up to 30 vol.% BaTiO 3 agreed well with the Bruggeman model. These results demonstrate the potential of facile surface hydroxylation of nanoparticles towards the fabrication of higher energy-density nanocomposites. © 2012 The Royal Society of Chemistry.

  5. Systèmes luminescents BaTiO3 : Ln(Ln= Er3+, Yb3+, Eu3+) préparés par chimie douce : poudres, nanopoudres et films nanostructurés

    OpenAIRE

    Garcia-Hernandez, Margarita

    2010-01-01

    This work was focused to the preparation of BaTiO3 powders, nanoparticles and films synthesized by solid state route, hydrothermal and sol-gel methods as well as to the study to structural and optical properties. BaTiO3 perovskite has the capability to incorporate rare earth ions of different size exhibiting luminescent properties, specifically when is doped by Eu3+, Er3+ and Yb3+ ions, also, these ions can be employed as optical probe in this matrix. Europium doped barium titanate prepared b...

  6. Structural and ferroelectric properties of BaTiO 3/YBa 2Cu 3O 7 heterostructures prepared by laser molecular beam epitaxy

    Science.gov (United States)

    Wang, H. S.; Liu, Y. W.; Ma, K.; Peng, Z. Q.; Cui, D. F.; Lu, H. B.; Zhou, Y. L.; Chen, Z. H.; Li, L.; Yang, G. Z.

    1997-08-01

    Heteroepitaxial BaTiO 3(BTO)/YBa 2Cu 3O 7(YBCO) thin films were grown on (100) SrTiO 3(STO) substrates by ozone assistant laser molecular beam epitaxy (L sbnd MBE). The results show that by using this technique, high quality ferroelectric/superconductor heterostructures with high crystalline quality and desirable device performance can be obtained.

  7. Dielectric Behavior of BaTiO3/PVDF Nanocomposites In-situ Synthesized by the Sol-Gel Method

    Institute of Scientific and Technical Information of China (English)

    DONG Li-jie; XIONG Chuan-xi; CHEN Juan; NAN Ce-wen

    2004-01-01

    BaTiO3/ PVDF nanocomposites were prepared via in-situ growth of nanosized BaTiO3 particlesin PVDF matrix by using the solgel method. The present elements of BaTiO3/ PVDF nanocomposites were ana-lyzed by an electron probe X-ray microanalyser. Nanosized BaTiO3 grown in the composite films was characterizedby an X-ray diffractometer and a transmission electron microscope, and the dielectric properties of the compositefilms were measured. The distribution of BaTiO3 nanoparticles in-situ grown in the PVDF matrix was examined us-ing a scanning electron microscope.

  8. Strain-induced magnetic domain wall control by voltage in hybrid piezoelectric BaTiO3 ferrimagnetic TbFe structures.

    Science.gov (United States)

    Rousseau, Olivier; Weil, Raphael; Rohart, Stanislas; Mougin, Alexandra

    2016-01-01

    This paper reports on the voltage dependence of the magnetization reversal of a thin amorphous ferromagnetic TbFe film grown on a ferroelectric and piezoelectric BaTiO3 single crystal. Magneto-optical measurements, at macroscopic scale or in a microscope, demonstrate how the ferroelectric BaTiO3 polarisation history influences the properties of the perpendicularly magnetized TbFe film. Unpolarised and twinned regions are obtained when the sample is zero voltage cooled whereas flat and saturated regions are obtained when the sample is voltage cooled through the ferroelectric ordering temperature of the BaTiO3 crystal, as supported by atomic force microscopy experiments. The two steps involved in the TbFe magnetization reversal, namely nucleation and propagation of magnetic domain walls, depend on the polarisation history. Nucleation is associated to coupling through strains with the piezoelectric BaTiO3 crystal and propagation to pinning with the ferroelastic surface patterns visible in the BaTiO3 topography. PMID:26987937

  9. Leakage current transport mechanisms of La0.67Sr0.33MnO3/BaTiO3 bilayer films grown on Nb:SrTiO3

    Indian Academy of Sciences (India)

    Pan Ruikun; Liu Panke; Li Mingkai; Tao Haizheng; Li Pai; He Yunbin

    2015-06-01

    La0.67Sr0.33MnO3/BaTiO3(LSMO/BTO) bilayer films were epitaxially grown on Nb:SrTiO3 (NSTO) substrates by the pulsed laser deposition technique. Current–voltage (–) characteristics of the LSMO/BTO bilayer films were studied. – curves were measured at room temperature, which show rectifying behaviour and can be well fitted by the space-charge-limited current mechanism under forward bias while thermionic emission model under reverse bias. Analysis indicates that a modulating Schottky barrier exists at the LSMO/BTO interface, which dominates the leakage current transport properties of LSMO/BTO bilayer films.

  10. In situ stress measurements during pulsed laser deposition of BaTiO3 and SrTiO3 atomic layers on Pt(0 0 1)

    Science.gov (United States)

    Premper, J.; Sander, D.; Kirschner, J.

    2015-04-01

    We apply the cantilever deflection technique to measure stress in nm thin BaTiO3 and SrTiO3 films during pulsed laser deposition on a Pt(0 0 1) single crystal cantilever substrate. We find a compressive film stress of -4.2 GPa for BaTiO3 on Pt(0 0 1) (misfit = -2.3%), whereas the deposition of SrTiO3 (misfit = +0.4%) induces a tensile stress of +1.5 GPa. The stress measurements are augmented by in situ low energy electron diffraction experiments which indicate an epitaxial order of the films. We apply continuum elasticity to calculate film stress. We conclude that sign and magnitude of the measured stress are due to the epitaxial misfit between film and substrate, which is -2.3% and +0.4% for BaTiO3 and SrTiO3, respectively. We identify that in addition to misfit also the oxygen partial pressure during PLD film growth influences film stress. PLD growth in an oxygen-free environment leads to factor of two increased tensile stress in SrTiO3 on Pt(0 0 1) as compared to growth at pO2 =10-4 mbar. The role of film stoichiometry for film stress is discussed.

  11. Basic thin film processing for high-Tc superconductors

    International Nuclear Information System (INIS)

    Much attention has been paid for the thin films of perovskite-type oxides especially for the thin films of the high-Tc superconducting ceramics. Historically the thin films of the perovskite-type oxides have been studied as a basic research for ferroelectric materials. Thin films of BaTiO3 and PbTiO3 were tried to deposited and there ferroelectricity was evaluated. Recently this kind of perovskite thin films, including PZT (PbTiO3-PbZrO3) and PLZT [(Pb, La) (Zr, T)O3] have been studied in relation to the synthesis of thin film dielectrics, pyroelectrics, piezoelectrics, electro-optic materials, and acousto-optic materials. Thin films of BPB (BaPbO3- BaBiO3) were studied as oxide superconductors. At present the thin films of the rare-earth high-Tc superconductors of LSC (La1-xSrxCuO4) and YBC (YBa2Cu3O7-δ) have been successfully synthesized owing to the previous studies on the ferroelectric thin films of the perovskite- type oxides. Similar to the rare-earth high-Tc superconductors thin films of the rare-earth-free high-Tc superconductors of BSCC (Bi-Sr-Ca-Cu-O)9 and TBCC (Tl- Ba-Ca-Cu-O)10 system have been synthesized. In this section the basic processes for the fabrication of the high- Tc perovskite superconducting thin films are described

  12. SiO2表面包覆改性钛酸钡/聚酰亚胺复合薄膜的制备与性能∗%Preparation and dielectric property of SiO2 surface coating modified BaTiO3/polyimide composite film

    Institute of Scientific and Technical Information of China (English)

    王亚军; 武晓娟; 冯长根; 曾庆轩

    2015-01-01

    以聚酰亚胺(PI)为基体,将聚酰亚胺与钛酸钡(BaTiO3)纳米粒子进行复合,采用原位聚合法制备BaTiO3/PI复合薄膜.为提高 BaTiO3纳米粒子的分散性和表面性能,采用 SiO2对 BaTiO3纳米粒子进行表面包覆改性,并制备改性 BaTiO3/PI 复合薄膜.采用红外光谱、X射线衍射、扫描电镜等对制备得到的改性BaTiO3进行了表征,测试了复合薄膜的介电性能.结果发现,SiO2与BaTiO3粒子间仅是物理包覆,没有新物质形成.测试频率为103 Hz 时,质量分数为5%的SiO2包覆改性使复合薄膜的介电常数增大到21.8,介电损耗为0.00521,击穿强度为76 MV/m,储能密度为0.56 J/cm3.研究表明,采用 SiO2对 BaTiO3改性使得复合薄膜的介电性能有所提高.%Polyimide (PI)was chosen as the matrix of the composite,barium titanate/polyimide (BaTiO3/PI) nanocomposite films were prepared with in situ polymerization.In order to improve the dispersion and the phys-ical-chemical properties of BT surface,barium titanate was modified by SiO2 coating and modified barium titan-ate/polyimide (BaTiO3/PI)nanocomposite films were prepared.The prepared modified BaTiO3 was character-ized by X-ray diffraction (XRD)analysis,Fourier transform infrared spectroscopy (FT-IR)and scanning elec-tron microscopy (SEM),and the dielectric properties of the composites were characterized in detail.It was shown that surface modification with SiO2 was the physical effect and there were no new substances forming. When BaTiO3 was modified by 5% SiO2 ,the dielectric constant of the composite film was 21.8 (103 Hz),the loss tangent 0.00521,breakdown strength 76 MV/m,energy storage density 0.56 J/cm3 .The BaTiO3 surface coating modification by SiO2 was beneficial to the dielectric properties of the BaTiO3/PI composite film.

  13. Large enhancement of magnetic anisotropy and laser induced resistive switching effect in La0.7Sr0.3MnO3 films due to strain from BaTiO3 substrates

    Science.gov (United States)

    Kalappattil, V.; Das, R.; Srikanth, H.; Phan, M. H.; Moya, X.

    Multifunctional oxide materials are interesting for their fundamental physical properties and technological applications. Epitaxial films of La0.7Sr0.3MnO3 (LSMO) on BaTiO3 (BTO) show intriguing properties such as a giant magnetoelectric effect due to strain from BTO substrate. The LSMO film shows sharp jumps in magnetization M(T) and resistance R(T) at first-order structural phase transitions of BTO (TR-O 200K and TO-T 270 K) due to strain coupling from BTO. A temperature evolution of effective in-plane anisotropy field (HK) measured using the radio-frequency transverse susceptibility (TS) shows a sharp increase in HK around TR-O, which vanishes around TO-T.The in-plane magnetic anisotropy plays an important role in changing the magnetic and resistive states around TO-T. A switchable laser-induced resistive change of up to 300 %, which is about 10 times greater than those of conventional oxide systems, has been achieved in LSMO films using a 0.5 W violet laser just below the TO-T.The repeatability and stability of the laser-induced resistive switching effect reveal potential applications of LSMO/BTO heterostructures in developing new type of temperature sensors and memory devices. Work at USF supported by ARO Grant No. W911NF-15-1-0626.

  14. Synthesis of self-assembly BaTiO3 nanowire by sol-gel and microwave method

    International Nuclear Information System (INIS)

    Self-assembly ferroelectric BaTiO3 nanowires were fabricated using sol-gel and microwave method. The X-ray diffraction patterns show that BaTiO3 nanowires belong to the tetragonal perovskite structure. An increase in the intensity of (1 1 0) peak was observed as the annealing time increased. The shape of BaTiO3 nanowires microwave-annealed for different minutes was investigated using atomic force microscopy. It is found that nanowires of BaTiO3 annealed for 2.5 min are very clear-cut, orderly and almost uninterrupted. The height of nanowire is near to the film thickness. However, nanowires of BaTiO3 annealed for 5 min are lesser, shorter and lower, and the distances among these nanowires are wider and well-proportioned. The origin of the distinct differences due to the remotion of atoms obtained enough energy was discussed.

  15. Strongly enhanced flux pinning in the YBa2Cu3O7 -x films with the co-doping of BaTiO3 nanorod and Y2O3 nanoparticles at 65 K

    Science.gov (United States)

    Wang, Hong-Yan; Ding, Fa-Zhu; Gu, Hong-Wei; Zhang, Teng

    2015-09-01

    YBa2Cu3O7 - x (YBCO) films with co-doping BaTiO3 (BTO) and Y2O3 nanostructures were prepared by metal organic deposition using trifluoroacetates (TFA-MOD). The properties of the BTO/Y2O3 co-doped YBCO films with different excess yttrium have been systematically studied by x-ray diffraction (XRD), Raman spectra, and scanning electron microscope (SEM). The optimized content of yttrium excess in the BTO/Y2O3 co-doped YBCO films is 10 mol.%, and the critical current density is as high as ˜17 mA/cm2 (self-field, 65 K) by the magnetic signal. In addition, the Y2Cu2O5 was formed when the content of yttrium excess increases to 24 mol.%, which may result in the deterioration of the superconducting properties and the microstructure. The unique combination of the different types of nanostructures of BTO and Y2O3 in the doped YBCO films, compared with the pure YBCO films and BTO doped YBCO films, enhances the critical current density (JC) not only at the self-magnetic field, but also in the applied magnetic field. Project supported by the National Natural Science Foundation of China (Grant No. 51272250), the National Basic Research Program of China (Grant No. 2011CBA00105), the National High Technology Research and Development Program of China (Grant No. 2014AA032702), and the Natural Science Foundation of Beijing, China (Grant No. 2152035).

  16. La-doped BaTiO3 heterostructures: Compensating the polarization discontinuity

    Directory of Open Access Journals (Sweden)

    D. P. Kumah

    2013-12-01

    Full Text Available We demonstrate a route to manipulate the polarization and internal electric field of a complex oxide heterostructure using a layering sequence based on the LaAlO3-SrTiO3 interface. By combining sensitive atomic-level mapping of the structure using direct x-ray phase-retrieval methods with theoretical modeling of the electrostatic charge and polarization, we have devised a novel single-domain polar heterostructure. We find that ionic rearrangement results in strain and free energy minimization, and eliminates the polarization discontinuity leading to a two-fold increase of the spontaneous polarization towards the surface of an ultra-thin single-domain BaTiO3 film.

  17. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  18. BaTiO3 and polypropylene nanocomposites for capacitor applications

    Science.gov (United States)

    Dong, Daxuan; Tang, Longxiang; Zhu, Lei; Lee, Je; Case Western Reserve University Collaboration; Agiltron, Inc Collaboration

    2013-03-01

    A novel strategy to uniformly disperse 70-nm BaTiO3 ferroelectric nanoparticles in a dielectric polypropylene (PP) matrix is developed in order to achieve high dielectric constant and high energy density for capacitor applications. By modifying BaTiO3 surface with a bis-phosphonic acid-terminated polyhedral oligomeric selsisquioxane (POSS), a nanocomposite with BaTiO3@POSS uniformly dispersed in PP matrix was achieved. The nanocomposite film containing a high nanoparticle content of 30 vol.% exhibited a high dielectric constant of 32 and a breakdown voltage of 220 MV/m, but with a high energy loss. Improvement of this nanocomposite by understanding the interfacial polarization is carried out in this work. The dielectric constant difference between BaTiO3 and PP can generate interfacial polarization and subsequent internal conduction in BaTiO3 particles upon bipolar polarization. Reduction of this internal conduction mechanism will significantly reduce the hysteresis loss in polymer nanodielectrics.

  19. Nanomechanics of Ferroelectric Thin Films and Heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan; Hu, Shenyang Y.; Chen , L.Q.

    2016-08-31

    The focus of this chapter is to provide basic concepts of how external strains/stresses altering ferroelectric property of a material and how to evaluate quantitatively the effect of strains/stresses on phase stability, domain structure, and material ferroelectric properties using the phase-field method. The chapter starts from a brief introduction of ferroelectrics and the Landau-Devinshire description of ferroelectric transitions and ferroelectric phases in a homogeneous ferroelectric single crystal. Due to the fact that ferroelectric transitions involve crystal structure change and domain formation, strains and stresses can be produced inside of the material if a ferroelectric transition occurs and it is confined. These strains and stresses affect in turn the domain structure and material ferroelectric properties. Therefore, ferroelectrics and strains/stresses are coupled to each other. The ferroelectric-mechanical coupling can be used to engineer the material ferroelectric properties by designing the phase and structure. The followed section elucidates calculations of the strains/stresses and elastic energy in a thin film containing a single domain, twinned domains to complicated multidomains constrained by its underlying substrate. Furthermore, a phase field model for predicting ferroelectric stable phases and domain structure in a thin film is presented. Examples of using substrate constraint and temperature to obtain interested ferroelectric domain structures in BaTiO3 films are demonstrated b phase field simulations.

  20. Preparation and Microstructure of Highly - Oriented LaNiO3 Thin Films by RF Sputtering Method

    Institute of Scientific and Technical Information of China (English)

    CHENG Xing-hua; QIAO Liang; BI Xiao-fang

    2006-01-01

    In an attempt of being used as buffer layers and electrodes for the textured BaTiO3 (BTO) ferroelectric thin films, highly (100)-oriented LaNiO3 (LNO) thin films of different thicknesses were deposited directly on Si (100) substrate with radio-frequency (RF) magnetron sputtering method. It is observed that the substrate temperatures and the film thicknesses bring main influences on the microstructures and orientation of the thin film. The effects of the thicknesses and substrate temperatures on the orientation of the films were studied on the LNO films of different thicknesses. The highly (100)-oriented LNO thin films were obtained at the substrate temperature of 600 ℃. The existence of epitaxially grown BTO films indicates that the oriented LNO thin films obtained in this work could be used as a buffer layer for epitaxial growth.

  1. Fast Molecular-Dynamics Simulation for Ferroelectric Thin-Film Capacitors Using a First-Principles Effective Hamiltonian

    OpenAIRE

    Nishimatsu, Takeshi; Waghmare, Umesh V.; Kawazoe, Yoshiyuki; Vanderbilt, David

    2008-01-01

    A newly developed fast molecular-dynamics method is applied to BaTiO3 ferroelectric thin-film capacitors with short-circuited electrodes or under applied voltage. The molecular-dynamics simulations based on a first-principles effective Hamiltonian clarify that dead layers (or passive layers) between ferroelectrics and electrodes markedly affect the properties of capacitors, and predict that the system is unable to hop between a uniformly polarized ferroelectric structure and a striped ferroel...

  2. Ultrafast magneto-optical spectroscopy of BiFeO3-BaTiO3 based structures

    Science.gov (United States)

    Magill, Brenden A.; Bishop, Michael; McGill, Stephen A.; Zhou, Yuon; Chopra, Anuj; Maurya, Deepam; Song, Hyun-Cheol; Priya, Shashank; Khodaparast, Giti A.

    2015-09-01

    Ultrafast optical spectroscopy can provide insight into fundamental microscopic interactions, dynamics and the coupling of several degrees of freedom. Pump/ probe studies can reveal the answer to questions like "What are the achievable switching speeds in multiferroics?", "What is the influence of the crystallographic orientation and domain states on the available switching states?", and "What is the effect of the hetrostructure on promoting the coupling between the varying field excitations?". In this presentation, we report on two color (400/800nm) ultrafast pump-probe differential reflectance spectroscopy of BiFeO3-BaTiO3 structures to probe the coupling between optical and acoustic phonons to spin waves. The data presented here is a combination of different transient reflectivity measurements to probe both the carrier and spin dynamics. The (001)-BiFeO3-BaTiO3 thin films were prepared using pulsed laser deposition on vicinal SrTiO3 substrates using La0.70 Sr0.30MnO3 bottom electrodes. Crystal orientation and topography were analyzed by x-ray diffraction and atomic force microscopy. . Our results are important to developing devices on the basis of this material system. This work was supported by the AFOSR through grant FA9550-14-1-0376,NSF-Career Award DMR-0846834, and the Virginia Tech Institute for Critical Technology and Applied Science.

  3. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

  4. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  5. Effect of electromechanical boundary conditions on the properties of epitaxial ferroelectric thin films

    Institute of Scientific and Technical Information of China (English)

    Zhou Zhi-Dong; Zhang Chun-Zu; Jiang Quan

    2011-01-01

    The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzburg-Landau equation (DGLE).The numerical solution for BaTiO3 film shows that internal stress and the depolarization field have the most effects on ferroelectric properties such as polarization,Curie temperature and susceptibility.With the increase of the thickness of the film,the polarization of epitaxial ferroelectric thin film is enhanced rapidly under high internal compressively stress.With the thickness exceeding the critical thickness for dislocation formation,the polarization increases slowly and even weakens due to relaxed internal stresses and a weak electrical boundary condition.This indicates that the effects of mechanical and electrical boundary conditions both diminish for ferroelectric thick films.Consequently,our thermodynamic method is a full scale model that can predict the properties of ferroelectric perovskite films in a wide range of film thickness.

  6. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  7. Thin films on cantilevers

    NARCIS (Netherlands)

    Nazeer, Hammad

    2012-01-01

    The main goal of the work compiled in this thesis is to investigate thin films for integration in micro electromechanical systems (MEMS). The miniaturization of MEMS actuators and sensors without compromising their performance requires thin films of different active materials with specific propertie

  8. A phase-field study of the scaling law in free-standing ferroelectric thin films

    Science.gov (United States)

    Yin, Binglun; Mao, Huina; Qu, Shaoxing

    2015-12-01

    The scaling law for ferroelectric stripe domains is investigated in free-standing BaTiO3 and PbTiO3 thin films via phase-field simulations. The results agree with the Kittel law, where the square of the domain width is found to be proportional to the thin film thickness. After being rescaled by the corresponding domain wall thickness, the generalized scaling law is also demonstrated, with the dimensionless scaling constant M estimated to be ˜3.3 in two ferroelectric materials. Moreover, we predict the effect of the exchange constant which is incorporated in Ginzburg-Landau theory on the equilibrium domain width and the critical thickness of the ferroelectric thin films.

  9. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  10. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

  11. Evaporated VOx Thin Films

    Science.gov (United States)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  12. Electrical properties of resistive switches based on Ba1-χSrχTiO3 thin films prepared by RF co-sputtering

    International Nuclear Information System (INIS)

    In this work, was proposed the use of Ba1-χSrχTiO3(0≤x≤1) thin films for the construction of metal-insulator-metal heterostructures; and their great potential for the development of non-volatile resistance memories (ReRAM) is shown. The deposition of Ba1-χSrχTiO3 thin films was done by the RF co-sputtering technique using two magnetron sputtering cathodes with BaTiO3 and SrTiO3 targets. The chemical composition (x parameter) in the deposited Ba1-χSrχTiO3 thin films was varied through the RF powder applied to the targets. The constructed metal-insulator-metal heterostructures were Al/Ba1-χSrχTiO3/nichrome. The I-V measurements of the heterostructures showed that their hysteretic characteristics change depending on the Ba/Sr ratio of the Ba1-χSrχTiO3 thin films; the Ba/Sr ratio was determined by employing the energy dispersive spectroscopy; Sem micrographs showed that Ba1-χSrχTiO3 thin films were uniform without cracks or pinholes. Additionally, the analysis of the X-ray diffraction results indicated the substitutional incorporation of Sr into the BaTiO3 lattice and the obtainment of crystalline films for the entire range of the x values. (Author)

  13. Heterogeneity in Polymer Thin Films

    OpenAIRE

    Kanaya, Toshiji; Inoue, Rintaro; Nishida, Koji

    2011-01-01

    In the last two decades very extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties. One of the most interesting findings is the decrease in glass transition temperature Tg with film thickness in polystyrene (PS) thin film supported on Si substrate. Another interesting finding is apparent negative thermal expansivity in glassy state for thin films below ∼25 nm. In order to understand the unusual properties of polymer thin films we have st...

  14. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

  15. Thin film photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K; Ullal, H S

    1989-05-01

    Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

  16. Thin film temperature sensor

    Science.gov (United States)

    Grant, H. P.; Przybyszewski, J. S.

    1980-01-01

    Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

  17. Thin Film Microbatteries

    International Nuclear Information System (INIS)

    Thin film batteries are built layer by layer by vapor deposition. The resulting battery is formed of parallel plates, much as an ordinary battery construction, just much thinner. The figure (Fig. 1) shows an example of a thin film battery layout where films are deposited symmetrically onto both sides of a supporting substrate. The full stack of films is only 10 to 15 (micro)m thick, but including the support at least doubles the overall battery thickness. When the support is thin, the entire battery can be flexible. At least six companies have commercialized or are very close to commercializing such all-solid-state thin film batteries and market research predicts a growing market and a variety of applications including sensors, RFID tags, and smarter cards. In principle with a large deposition system, a thin film battery might cover a square meter, but in practice, most development is targeting individual cells with active areas less than 25 cm2. For very small battery areas, 2, microfabrication processes have been developed. Typically the assembled batteries have capacities from 0.1 to 5 mAh. The operation of a thin film battery is depicted in the schematic diagram (Fig. 2). Very simply, when the battery is allowed to discharge, a Li+ ion migrates from the anode to the cathode film by diffusing through the solid electrolyte. When the anode and cathode reactions are reversible, as for an intercalation compound or alloy, the battery can be recharged by reversing the current. The difference in the electrochemical potential of the lithium determines the cell voltage. Most of the thin films used in current commercial variations of this thin film battery are deposited in vacuum chambers by RF and DC magnetron sputtering and by thermal evaporation onto unheated substrates. In addition, many publications report exploring a variety of other physical and chemical vapor deposition processes, such as pulsed laser deposition, electron cyclotron resonance sputtering, and

  18. Thin film superfluid optomechanics

    CERN Document Server

    Baker, Christopher G; McAuslan, David L; Sachkou, Yauhen; He, Xin; Bowen, Warwick P

    2016-01-01

    Excitations in superfluid helium represent attractive mechanical degrees of freedom for cavity optomechanics schemes. Here we numerically and analytically investigate the properties of optomechanical resonators formed by thin films of superfluid $^4$He covering micrometer-scale whispering gallery mode cavities. We predict that through proper optimization of the interaction between film and optical field, large optomechanical coupling rates $g_0>2\\pi \\times 100$ kHz and single photon cooperativities $C_0>10$ are achievable. Our analytical model reveals the unconventional behaviour of these thin films, such as thicker and heavier films exhibiting smaller effective mass and larger zero point motion. The optomechanical system outlined here provides access to unusual regimes such as $g_0>\\Omega_M$ and opens the prospect of laser cooling a liquid into its quantum ground state.

  19. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  20. Phase transition in ZnS thin film phosphor

    Science.gov (United States)

    Kryshtab, T.; Khomchenko, V. S.; Andraca-Adame, J. A.; Khachatryan, V. B.; Mazin, M. O.; Rodionov, V. E.; Mukhlio, M. F.

    2005-02-01

    The effect of an original non-vacuum annealing of thin ZnS films according to the annealing conditions and type of substrate on the film's crystalline structure and surface morphology in relation with photoluminescent (PL) properties was investigated. ZnS thin films were deposited by electron-beam evaporation (EBE) on ceramic (BaTiO 3) and glass substrates heated to 150-200 °C. Three types of the targets such as ZnS, ZnS:Cu and ZnS:Cu, Al were used. The film thickness varied from 0.6 to 1 μm. As-deposited films were annealed at the atmospheric pressure in S 2-rich ambient atmosphere at 600-950 °C for 1 h. The ZnS:Cu films were Ga co-doped by annealing in the same atmosphere and temperature with additional Ga vapor. The ZnS films were doped with Cu, Cl using the thermal diffusion method by embedding the samples in ZnS:Cu, Cl powder. X-ray diffraction (XRD) technique, atomic force microscopy (AFM) and the measurements of PL parameters were used for investigation. The temperature of the ZnS phase transition from the sphalerite to wurtzite structure depends on the presence, type and ratio of additional impurities. It was revealed that Ga and Cl act not only as co-dopant to improve the luminescent properties, but also as activators of recrystallization processes. The transition of ZnS film's sphalerite lattice to wurtzite leads to the displacement of the blue emission band position towards the short-wavelength range by 10 nm.

  1. Ferroelectricity and antiferroelectricity of doped thin HfO2-based films.

    Science.gov (United States)

    Park, Min Hyuk; Lee, Young Hwan; Kim, Han Joon; Kim, Yu Jin; Moon, Taehwan; Kim, Keum Do; Müller, Johannes; Kersch, Alfred; Schroeder, Uwe; Mikolajick, Thomas; Hwang, Cheol Seong

    2015-03-18

    The recent progress in ferroelectricity and antiferroelectricity in HfO2-based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O3, BaTiO3, and SrBi2Ta2O9, which are considered to be feasible candidate materials for non-volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si-compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si-doped HfO2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro-electricity or antiferroelectricity in thin HfO2 films. They have large remanent polarization of up to 45 μC cm(-2), and their coercive field (≈1-2 MV cm(-1)) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field-effect-transistors and three-dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid-state-cooling, and infrared sensors. PMID:25677113

  2. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  3. Thin films for material engineering

    Science.gov (United States)

    Wasa, Kiyotaka

    2016-07-01

    Thin films are defined as two-dimensional materials formed by condensing one by one atomic/molecular/ionic species of matter in contrast to bulk three-dimensional sintered ceramics. They are grown through atomic collisional chemical reaction on a substrate surface. Thin film growth processes are fascinating for developing innovative exotic materials. On the basis of my long research on sputtering deposition, this paper firstly describes the kinetic energy effect of sputtered adatoms on thin film growth and discusses on a possibility of room-temperature growth of cubic diamond crystallites and the perovskite thin films of binary compound PbTiO3. Secondly, high-performance sputtered ferroelectric thin films with extraordinary excellent crystallinity compatible with MBE deposited thin films are described in relation to a possible application for thin-film MEMS. Finally, the present thin-film technologies are discussed in terms of a future material science and engineering.

  4. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  5. NMR characterization of thin films

    Science.gov (United States)

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  6. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T. [Sandia National Laboratories, Albuquerque, NM (United States)] [and others

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  7. Protein Thin Film Machines

    OpenAIRE

    Federici, Stefania; Oliviero, Giulio; Hamad-Schifferli, Kimberly; Bergese, Paolo

    2010-01-01

    We report the first example of microcantilever beams that are reversibly driven by protein thin film machines fuelled by cycling the salt concentration of the surrounding solution. We also show that upon the same salinity stimulus the drive can be completely reversed in its direction by introducing a surface coating ligand. Experimental results are throughout discussed within a general yet simple thermodynamic model.

  8. [Spectral emissivity of thin films].

    Science.gov (United States)

    Zhong, D

    2001-02-01

    In this paper, the contribution of multiple reflections in thin film to the spectral emissivity of thin films of low absorption is discussed. The expression of emissivity of thin films derived here is related to the thin film thickness d and the optical constants n(lambda) and k(lambda). It is shown that in the special case d-->infinity the emissivity of thin films is equivalent to that of the bulk material. Realistic numerical and more precise general numerical results for the dependence of the emissivity on d, n(lambda) and k(lambda) are given.

  9. Thin film superconductor magnetic bearings

    Science.gov (United States)

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  10. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  11. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  12. Thin film processes

    CERN Document Server

    Vossen, John L

    1978-01-01

    Remarkable advances have been made in recent years in the science and technology of thin film processes for deposition and etching. It is the purpose of this book to bring together tutorial reviews of selected filmdeposition and etching processes from a process viewpoint. Emphasis is placed on the practical use of the processes to provide working guidelines for their implementation, a guide to the literature, and an overview of each process.

  13. Experimental and numerical studies of microwave properties of BaTiO3-Pt composites

    Science.gov (United States)

    Kuga, Yasuo; Lee, Seung-Woo; Almajid, Abdulhakim; Taya, Minoru; Li, Jing-Feng; Watanabe, Ryuzo

    2002-10-01

    In this paper, we will present the experimental results of the microwave properties of BaTiO3 and BaTiO3-Pt composites. These composites materials were designed to increase the effective dielectric constant at microwave frequency. Three different platinum volume fractions were used, 3, 5 and 10%, to make BaTiO3-Pt composites, in addition to a pure BaTiO3 material. To characterize the BaTiO3-Pt composites, microwave measurements were conducted using the waveguide transmission measurements. The experimental results verify that it is possible to increase the dielectric constant using the conductor loading method.

  14. Thin film interconnect processes

    Science.gov (United States)

    Malik, Farid

    Interconnects and associated photolithography and etching processes play a dominant role in the feature shrinkage of electronic devices. Most interconnects are fabricated by use of thin film processing techniques. Planarization of dielectrics and novel metal deposition methods are the focus of current investigations. Spin-on glass, polyimides, etch-back, bias-sputtered quartz, and plasma-enhanced conformal films are being used to obtain planarized dielectrics over which metal films can be reliably deposited. Recent trends have been towards chemical vapor depositions of metals and refractory metal silicides. Interconnects of the future will be used in conjunction with planarized dielectric layers. Reliability of devices will depend to a large extent on the quality of the interconnects.

  15. Handbook of thin film technology

    CERN Document Server

    Frey, Hartmut

    2015-01-01

    “Handbook of Thin Film Technology” covers all aspects of coatings preparation, characterization and applications. Different deposition techniques based on vacuum and plasma processes are presented. Methods of surface and thin film analysis including coating thickness, structural, optical, electrical, mechanical and magnetic properties of films are detailed described. The several applications of thin coatings and a special chapter focusing on nanoparticle-based films can be found in this handbook. A complete reference for students and professionals interested in the science and technology of thin films.

  16. Thin film mechanics

    Science.gov (United States)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  17. Polycrystalline thin film photovoltaic technology

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L.; Noufi, R.

    1991-03-01

    Low-cost, high-efficiency thin-film modules are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. In this paper we review the significant technical progress made in the following thin films: copper indium diselenide, cadmium telluride, and polycrystalline thin silicon films. Also, the recent US DOE/SERI initiative to commercialize these emerging technologies is discussed. 6 refs., 9 figs.

  18. Upconversion emission of BaTiO3:Er nanocrystals

    Indian Academy of Sciences (India)

    Pushpal Ghosh; Suparna Sadhu; Tapasi Sen; Amitava Patra

    2008-06-01

    Here, we report the dopant concentration and pump-power dependence upconversion emission properties of erbium doped BaTiO3 nanocrystals derived from sol–emulsion–gel method. Green (550 nm) and red (670 nm) upconversion emissions were observed at room temperature from the ${}^{4}S_{3/2}$ and ${}^{4}F_{9/2}$ levels of Er3+ : BaTiO3 nanocrystals. It is found that at 850 mW of cw excitation power (at 980 nm) the total luminescence was 17130 Cd/m2 for 1000°C heated 0.25 mol% Er-doped BaTiO3 nanocrystals. It is worthwhile to mention that the unusual power-dependent upconversion luminescence (saturation) is observed at higher dopant concentration (2.5 mol%) and high pump power. Our analysis confirms that the depletion of the excited state is responsible for the relevant fluorescence upconversion. We have again confirmed that a twophoton excited state absorption process occurs for all samples.

  19. Investigation on Silicon Thin Film Solar Cells

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The preparation, current status and trends are investigated for silicon thin film solar cells. The advantages and disadvantages of amorphous silicon thin film, polycrystalline silicon thin film and mono-crystalline silicon thin film solar cells are compared. The future development trends are pointed out. It is found that polycrystalline silicon thin film solar cells will be more promising for application with great potential.

  20. Heating effect of BaTiO3 in microwave field and microstructure of BaTiO3

    Institute of Scientific and Technical Information of China (English)

    李永伟; 刘韩星; 张汉林; 欧阳世翕

    1997-01-01

    Microwave equipment at 2 450 MHz was employed to prepare BaTiO3 The heating effect of thesystem in the microwave field,which was influenced by several factors including dielectric properties of synthesis system and thermal insulate structures,was discussed in detail.The heating rates of the synthesis system were mainly determined by BaCO3 and TiO2 at low temperature and by TiO2 and BaTiO3 at high temperature.The results show that the heating effects in microwave field are greatly different from those in conventional furnace.The reaction of BaCO3 and TiO2 only lasts for 3 min at 1 100℃,and the fine,narrow-distributed and well-crystallized powders were prepared.

  1. Effect of external stress on phase diagrams and dielectric properties of epitaxial ferroelectric thin films grown on orthorhombic substrates

    Institute of Scientific and Technical Information of China (English)

    L(U) Ye-gang; DENG Shui-feng; GONG Lun-jun; YANG Jian-tao

    2006-01-01

    A Landau-Ginsburg-Devonshire(LD)-type thermodynamic theory was used to describe the effect of external stress on phase diagrams and dielectric properties of epitaxial ferroelectric thin films grown on orthorhombic substrates which induce nonequally biaxial misfit strains in the films plane. The "misfit strain-external stress" and "external stress-temperature" phase diagrams were constructed for single-domain BaTiO3(BT) and PbTiO3(PT) thin films. It is shown that the external stress may lead to the rotation of the spontaneous polarization and a gradual change of its magnitude, which may result in phase transition. Nonequally biaxial misfit strains dependence of the stability of polarization states may be governed by external stress. At room temperature,stress-induced ferroelectric/paraelectric phase transition which occurs in film on cubic substrate does not take place in the ferroelectric thin film grown on orthorhombic substrate. It is also shown that the nonequally misfit strains in the film plane may lead to the appearance of new phases which do not form in films grown on cubic substrates under external stress. The dependence of the dielectric response on the external stress is also studied. It is shown that the dielectric constants of single-domain PT and BT films are very sensitive to the external stress under the given anisotropic misfit strains-temperature conditions. It presents theoretical evidence that the external stress and anisotropic misfit strains can be employed for improving the thin films physical properties.

  2. Heterogeneous distribution of B-site cations in BaZrxTi1-xO3 epitaxial thin films grown on (0 0 1) SrTiO3 by pulsed laser deposition

    Science.gov (United States)

    Ventura, J.; Polo, M. C.; Ferrater, C.; Hernández, S.; Sancho-Parramón, J.; Coy, L. E.; Rodríguez, L.; Canillas, A.; Fábrega, L.; Varela, M.

    2016-09-01

    The isovalent susbstitution of Ti4+ by Zr4+ in BaZrxTi1-xO3 modifies the dielectric character of ferroelectric BaTiO3 yielding different behaviours such as relaxor, polar cluster, etc. The dynamic coupling between BaTiO3 polar nanoregions and BaZrO3 nonpolar ones as well as microstrain between them are thought to be behind such a rich phase diagram. However, these short-range compositonal variations are elusive to detect and this topic is thus rarely addressed. We have grown epitaxial thin films of BaZrxTi1-xO3 on (0 0 1)-oriented SrTiO3 substrates by pulsed laser deposition sweeping the entire composition range between BaTiO3 and BaZrO3 in increments of 0.1 in x. Several characterization techniques (AFM, TEM, XRD, Raman spectroscopy) were used for this research in order to understand the morphological and structural properties of the deposited films. Ellipsometric measurements allowed the calculation of the band gap energy of the films. This work demonstrates the existence of a heterogeneous distribution in the substitution of titanium by zirconium yielding relaxor and polar cluster nanoregions.

  3. Influence of epitaxial strain on elastocaloric effect in ferroelectric thin films

    International Nuclear Information System (INIS)

    We report the influence of epitaxial strain um on the elastocaloric properties of BaTiO3 thin films. Using thermodynamic calculations, we show that there exists a critical compressive stress σ3c at which the elastocaloric effect is maximized for any compressive misfit strain we investigate. Moreover, it is found that |σ3c| decreases significantly with decreasing |um|, which is accompanied by a reduction of the elastocaloric response. Interestingly, a several fold enhancement in the electrocaloric effect can be achieved for stress in proximity of σ3c. The elastocaloric effect predicted here may find potential cooling applications by combining the stress-mediated electrocaloric effect or designing hybrid elastocaloric/electrocaloric devices in the future

  4. BaTiO3 supercages: unusual oriented nanoparticle aggregation and continuous ordering transition in morphology.

    Science.gov (United States)

    Li, Juan; Hietala, Sami; Tian, Xuelin

    2015-01-27

    Here we report the organic-free mesocrystalline superstructured cages of BaTiO3, i.e., the BaTiO3 supercages, which are synthesized by a one-step templateless and additive-free route using molten hydrated salt as the reaction medium. An unusual three-dimensional oriented aggregation of primary BaTiO3 nanoparticles in the medium of high ionic strength, which normally favors random aggregation, is identified to take place at the early stage of the synthesis. The spherical BaTiO3 aggregates further experience a remarkable continuous ordering transition in morphology, consisting of nanoparticle faceting and nanosheet formation steps. This ordering transition in conjunction with Ostwald ripening-induced solid evacuation leads to the formation of unique supercage structure of BaTiO3. Benefiting from their structure, the BaTiO3 supercages exhibit improved microwave absorption property. PMID:25514033

  5. Polycrystalline thin films

    Science.gov (United States)

    Zweibel, K.; Mitchell, R.; Ullal, H.

    1987-02-01

    This annual report for fiscal year 1986 summarizes the status, accomplishments, and projected future research directions of the Polycrystalline Thin Film Task in the Photovoltaic Program Branch of the Solar Energy Research Institute's Solar Electric Research Division. Subcontracted work in this area has concentrated on the development of CuInSe2 and CdTe technologies. During FY 1986, major progress was achieved by subcontractors in (1) achieving 10.5% (SERI-verified) efficiency with CdTe, (2) improving the efficiency of selenized CuInSe2 solar cells to nearly 8%, and (3) developing a transparent contact to CdTe cells for potential use in the top cells of tandem structures.

  6. Polyimide Aerogel Thin Films

    Science.gov (United States)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  7. Elemental intermixing within an ultrathin SrRuO3 electrode layer in epitaxial heterostructure BaTiO3/SrRuO3/SrTiO3

    Directory of Open Access Journals (Sweden)

    H. B. Zhang

    2016-01-01

    Full Text Available Aberration corrected scanning transmission electron microscopy is used to directly observe atom columns in an epitaxial BaTiO3 thin film deposited on a 3.6 nm-thick SrRuO3 electrode layer above an SrTiO3 (001 substrate. Compositional gradients across the heterointerfaces were examined using electron energy-loss spectroscopy techniques. It was found that a small amount of Ba and Ti had diffused into the SrRuO3 layer, and that this layer contained a non-negligible concentration of oxygen vacancies. Such point defects are expected to degrade the electrode’s electronic conductivity drastically, resulting in a much longer screening length. This may explain the discrepancy between experimental measurements and theoretical estimates of the ferroelectric critical thickness of a BaTiO3 ferroelectric barrier sandwiched between metallic SrRuO3 electrodes, since theoretical calculations generally assume ideal (stoichiometric perovskite SrRuO3.

  8. Elemental intermixing within an ultrathin SrRuO3 electrode layer in epitaxial heterostructure BaTiO3/SrRuO3/SrTiO3

    International Nuclear Information System (INIS)

    Aberration corrected scanning transmission electron microscopy is used to directly observe atom columns in an epitaxial BaTiO3 thin film deposited on a 3.6 nm-thick SrRuO3 electrode layer above an SrTiO3 (001) substrate. Compositional gradients across the heterointerfaces were examined using electron energy-loss spectroscopy techniques. It was found that a small amount of Ba and Ti had diffused into the SrRuO3 layer, and that this layer contained a non-negligible concentration of oxygen vacancies. Such point defects are expected to degrade the electrode’s electronic conductivity drastically, resulting in a much longer screening length. This may explain the discrepancy between experimental measurements and theoretical estimates of the ferroelectric critical thickness of a BaTiO3 ferroelectric barrier sandwiched between metallic SrRuO3 electrodes, since theoretical calculations generally assume ideal (stoichiometric) perovskite SrRuO3

  9. Thin functional conducting polymer films

    OpenAIRE

    Tian, S.

    2005-01-01

    In the present study, thin functional conducting polyaniline (PANI) films, either doped or undoped, patterned or unpatterned, were prepared by different approaches. The properties of the obtained PANI films were investigated in detail by a combination of electrochemistry with several other techniques, such as SPR, QCM, SPFS, diffraction, etc. The sensing applications (especially biosensing applications) of the prepared PANI films were explored. Firstly, the pure PANI films were prepar...

  10. Interfaces and thin films physics

    International Nuclear Information System (INIS)

    The 1988 progress report of the Interfaces and Thin Film Physics laboratory (Polytechnic School France) is presented. The research program is focused on the thin films and on the interfaces of the amorphous semiconductor materials: silicon and silicon germanium, silicon-carbon and silicon-nitrogen alloys. In particular, the following topics are discussed: the basic processes and the kinetics of the reactive gas deposition, the amorphous materials manufacturing, the physico-chemical characterization of thin films and interfaces and the electron transport in amorphous semiconductors. The construction and optimization of experimental devices, as well as the activities concerning instrumentation, are also described

  11. Thin-film solar cell

    NARCIS (Netherlands)

    Metselaar, J.W.; Kuznetsov, V.I.

    1998-01-01

    The invention relates to a thin-film solar cell provided with at least one p-i-n junction comprising at least one p-i junction which is at an angle alpha with that surface of the thin-film solar cell which collects light during operation and at least one i-n junction which is at an angle beta with t

  12. In-plane strain modulated magnetization and magnetoelectric effect in La0.7Sr0.3MnO3-BaTiO3 and La0.7Sr0.3MnO3-BaTiO3-BiFeO3 multilayer's

    Science.gov (United States)

    Kumar, Virendra; Gaur, Anurag; Chaudhury, Ram Janay; Kumar, Dileep

    2016-10-01

    La0.7Sr0.3MnO3-BaTiO3(LSMO/BTO) and La0.7Sr0.3MnO3-BaTiO3-BiFeO3 (LSMO/BTO/BFO) multilayer thin films are deposited on STO (100) substrate by pulsed laser deposition. In-plane lattice mismatch induced strain is thoroughly investigated with the conclusion, that upper BTO layer of bilayer resides in high strained state, while upper BFO layer of trilayer remains under partially relaxed state. Significantly higher value (∼20) of dielectric constant is observed for LSMO/BTO bilayer in compliance with its higher (12.28 μC/cm2) in-plane strain induced interfacial polarization, which exceeds (2.06 μC/cm2), the observed value of polarization for LSMO/BTO/BFO trilayer. In LSMO/BTO bilayer, antiferromagnetic LSMO phase coexists due to the existence of strong tensile strain between the interfaces, which causes the reduction in value of saturation magnetization up to 50.76 emu/cm3 in comparison to 145.01 emu/cm3 for LSMO/BTO/BFO trilayer. The maximum value of linear magnetoelectric coefficient (α31) observed for LSMO/BTO bilayer is 24.77 mV/cm-Oe, which is higher in comparison to 19.54 mV/cm-Oe for LSMO/BTO/BFO trilayer, where the upper layer undergoes less strain in comparison to the bilayer.

  13. Effect of biaxial strain induced by piezoelectric PMN-PT on the upconversion photoluminescence of BaTiO₃:Yb/Er thin films.

    Science.gov (United States)

    Wu, Zhenping; Zhang, Yang; Bai, Gongxun; Tang, Weihua; Gao, Ju; Hao, Jianhua

    2014-11-17

    Thin films of Yb3+/Er3+ co-doped BaTiO3 (BTO:Yb/Er) have been epitaxially grown on piezoelectric Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) substrates. Biaxial strain can be effectively controlled by applying electric field on PMN-PT substrate. A reversible, in situ and dynamic modification of upconversion photoluminescence in BTO:Yb/Er film was observed via converse piezoelectric effect. Detailed analysis and in situ X-ray diffraction indicate that such modulations are possibly due to the change in the lattice deformation of the thin films. This result suggests an alternative method to rationally tune the upconversion emissions via strain engineering. PMID:25402140

  14. Laser molecular-beam epitaxy and second-order optical nonlinearity of BaTiO3/SrTiO3 superlattices

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of c-axis oriented BaTiO3/SrTiO3 superlattices with the atomic-scale precision were epitaxially grown on single-crystal SrTiO3 (100) substrates using laser molecular-beam epitaxy (LMBE). A periodic modulation of the intensity of reflection high-energy electron diffraction (RHEED) in BaTiO3 and SrTiO3 layers was observed and attributed to the lattice-misfit-induced periodic variation of the terrace density in film surface. The relationship between the second-order nonlinear optical susceptibilities and the superlattice structure was systematically studied. The experimental and theoretical fitting results indicate that the second-order nonlinear optical susceptibilities of BaTiO3/SrTiO3 superlattices were greatly enhanced with the maximum value being more than one order of magnitude larger than that of bulk BaTiO3 crystal. The mechanism of the enhancement of the second-order optical nonlinearity was discussed by taking into account the stress-induced lattice distortion and polarization enhancement.

  15. Microemulsion mediated synthesis of BaTiO3 – Ag nanocomposites

    Directory of Open Access Journals (Sweden)

    Songhak Yoon

    2009-06-01

    Full Text Available BaTiO3 – Ag composite nanopowders were synthesized via microemulsion mediated synthesis through the hydrolytic decomposition of mixed metal alkoxide solutions as precursor for the BaTiO3 and the reduction of silver nitrate in the presence of polyvinylpyrrolidone (PVP as source for the Ag nanoparticles. The X-ray diffraction (XRD patterns indicate that BaTiO3 and Ag phases were successfully synthesized in the composite powders. Scanning electron microscopy (SEM and transmission electron microscopy (TEM show that the synthesized BaTiO3 nanoparticles were aggregates of nanosized primary particles as small as 10 nm in diameter and the average particle size of nanocrystalline Ag was about 100 nm. Calcination and sintering studies reveal that there exists a difference in the sintering behaviour of BaTiO3 and Ag in the composite nanopowders. Thermogravimetric analysis (TGA shows weight losses due to the burnout of organic residues arising from the synthesis, the release of water from the surface and separation of hydroxyl ions from the lattice of BaTiO3 nanoparticles. A dilatometric study of BaTiO3-Ag composite confi rmed a strong difference in the shrinkage behaviour compared to that of the pure BaTiO3 obtained by microemulsion mediated synthesis.

  16. Epitaxial thin films of ATiO(3-x)H(x) (A = Ba, Sr, Ca) with metallic conductivity.

    Science.gov (United States)

    Yajima, Takeshi; Kitada, Atsushi; Kobayashi, Yoji; Sakaguchi, Tatsunori; Bouilly, Guillaume; Kasahara, Shigeru; Terashima, Takahito; Takano, Mikio; Kageyama, Hiroshi

    2012-05-30

    Epitaxial thin films of titanium perovskite oxyhydride ATiO(3-x)H(x) (A = Ba, Sr, Ca) were prepared by CaH(2) reduction of epitaxial ATiO(3) thin films deposited on a (LaAlO(3))(0.3)(SrAl(0.5)Ta(0.5)O(3))(0.7) substrate. Secondary ion mass spectroscopy detected a substantial amount and uniform distribution of hydride within the film. SrTiO(3)/LSAT thin film hydridized at 530 °C for 1 day had hydride concentration of 4.0 × 10(21) atoms/cm(3) (i.e., SrTiO(2.75)H(0.25)). The electric resistivity of all the ATiO(3-x)H(x) films exhibited metallic (positive) temperature dependence, as opposed to negative as in BaTiO(3-x)H(x) powder, revealing that ATiO(3-x)H(x) are intrinsically metallic, with high conductivity of 10(2)-10(4) S/cm. Treatment with D(2) gas results in hydride/deuteride exchange of the films; these films should be valuable in further studies on hydride diffusion kinetics. Combined with the materials' inherent high electronic conductivity, new mixed electron/hydride ion conductors may also be possible. PMID:22563869

  17. Size effects in thin films

    CERN Document Server

    Tellier, CR; Siddall, G

    1982-01-01

    A complete and comprehensive study of transport phenomena in thin continuous metal films, this book reviews work carried out on external-surface and grain-boundary electron scattering and proposes new theoretical equations for transport properties of these films. It presents a complete theoretical view of the field, and considers imperfection and impurity effects.

  18. Nanotemplated lead telluride thin films

    OpenAIRE

    Li, Xiaohong; Nandhakumar, Iris S.; Attard, George S.; Markham, Matthew L.; Smith, David C.; Baumberg, Jeremy J.

    2009-01-01

    Direct lyotropic liquid crystalline templating has been successfully applied to produce nanostructured IV–VI semiconductor PbTe thin films by electrodeposition both on gold and n-type (100) silicon substrates. The PbTe films were characterized by transmission electron microscopy, X-ray diffraction and polarized optical microscopy and the results show that the films have a regular hexagonal nanoarchitecture with a high crystalline rock salt structure and exhibit strong birefringenc...

  19. Thin films and froth flotation

    International Nuclear Information System (INIS)

    The properties of thin, aqueous films on solid surfaces and their central role in the froth flotation process are discussed. The stability of these films can generally be described in terms of electrostatic and van der Waals forces. Significant experimental and theoretical advances are required in many areas (e.g. short range forces, film drainage) before a clear picture of the collision of, adhesion between and detachment of bubbles and particles will emerge. (orig.)

  20. Thin-film ternary superconductors

    International Nuclear Information System (INIS)

    Physical properties and preparation methods of thin film ternary superconductors, (mainly molybdenum chalcogenides) are reviewed. Properties discussed include the superconducting critical fields and critical currents, resistivity and the Hall effect. Experimental results at low temperatures, together with electron microscopy data are used to determine magnetic flux pinning mechanisms in films. Flux pinning results, together with an empirical model for pinning, are used to get estimates for possible applications of thin film ternary superconductors where high current densities are needed in the presence of high magnetic fields. The normal state experimental data is used to derive several Fermi surface parameters, e.g. the Fermi velocity and the effective Fermi surface area. (orig.)

  1. Dielectric response of polystyrene - BaTiO3 nanocomposites

    Science.gov (United States)

    Korotkova, Tatyana N.; Sysoev, Oleg I.; Belov, Pavel A.; Emelianov, Nikita A.; Velyaev, Yury O.; Mandalawi, Wissam M. Al; Korotkov, Leonid N.

    2016-07-01

    The series of composite materials based on polystyrene and non-ferroelectric BaTiO3 nanoparticles ((1-x)PS-xBT, where the volume concentration x = 0-1.0) was prepared. Their dielectric properties were studied within the temperature range 20-160 °C at the frequency of 100 kHz. It is found that an increase in the barium titanate concentration leads to increase of the both dielectric permittivity (ɛ) and dielectric losses (tgδ). The concentration dependence of ɛ can be described by the modified Kerner model. It was found that the glass transition in polystyrene matrix is diffused and its temperature is increased with concentration x.

  2. Birefringent non-polarizing thin film design

    Institute of Scientific and Technical Information of China (English)

    QI; Hongji; HONG; Ruijin; HE; Hongbo; SHAO; Jianda; FAN; Zh

    2005-01-01

    In this paper, 2×2 characteristic matrices of uniaxially anisotropic thin film for extraordinary and ordinary wave are deduced at oblique incidence. Furthermore, the reflectance and transmittance of thin films are calculated separately for two polarizations, which provide a new concept for designing non-polarizing thin films at oblique incidence. Besides, using the multilayer birefringent thin films, non-polarizing designs, such as beam splitter thin film at single wavelength, edge filter and antireflection thin film over visible spectral region are obtained at oblique incidence.

  3. Thin-film forces in pseudoemulsion films

    Energy Technology Data Exchange (ETDEWEB)

    Bergeron, V.; Radke, C.J. [California Univ., Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley Lab., CA (United States)

    1991-06-01

    Use of foam for enhanced oil recovery (EOR) has shown recent success in steam-flooding field applications. Foam can also provide an effective barrier against gas coning in thin oil zones. Both of these applications stem from the unique mobility-control properties a stable foam possesses when it exists in porous media. Unfortunately, oil has a major destabilizing effect on foam. Therefore, it is important for EOR applications to understand how oil destroys foam. Studies all indicate that stabilization of the pseudoemulsion film is critical to maintain foam stability in the presence of oil. Hence, to aid in design of surfactant formulations for foam insensitivity to oil the authors pursue direct measurement of the thin-film or disjoining forces that stabilize pseudoemulsion films. Experimental procedures and preliminary results are described.

  4. Synthesis and characterization of BaTiO3 ferroelectric material

    International Nuclear Information System (INIS)

    BaTiO3 powder was prepared at low temperatures using the solid-state reaction, starting with two different precursors; the BaCO3/TiO2 and the Ba(NO3)2/TiO2 powder mixtures. It was found that, a single phase BaTiO3 was formed after calcination at 750 degree C for 10 h and at 600 degree C for 6 h for the first and second mixtures, respectively. Thermal and XRD analyses were used to study the formation kinetics of BaTiO3. Contracting volume reaction model was found to control both reactions. The SEM of the as milled powder, TMA, TG and thermodynamics analysis have been used to propose a realistic approach describing the reaction mechanism of BaTiO3. Characterization and the dielectric properties of the sintered BaTiO3 were investigated. The relative permittivity and the dielectric loss measured at room temperature and at 1 khz were 2028.5 and 0.043 for BaTiO3 prepared from BaCO3/TiO2, while they were 1805.33 and 0.41 for BaTiO3 prepared from Ba(NO3)2/TiO2.

  5. Thin films under chemical stress

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  6. Semiconductor-nanocrystal/conjugated polymer thin films

    Science.gov (United States)

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  7. EELS study on BST thin film under electron beam irradiation

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    [11]Yoshiya, M., Tanaka, I., Kaneko, K. et al., First principles calculation of chemical shifts in ELNES/NEXAFS of titanium oxides, J. Phys.: Condens. Matter., 1999, 11: 3217 -3228.[12]Egerton, R. F., Electron Energy-Loss Spectroscopy in the Electron Microscope, New York: Plenum Press,www.scichina.com1996, 245-300.[13]Smyth, D. M., Harmer, M. P., Peng, P., Defect chemistry of relaxor ferroelectrics and the implications for dielectric degradation, J. Am. Ceram. Soc., 1989, 72 (12): 2276-2278.[14]Chan, N. H., Sharma, R. K., Smyth, D. M., Nonstoichiometry in undoped BaTiO3, J. Am. Ceram. Soc., 1981,64 (9): 556-562.[15]Leapman, R. D., Grunes, L. A., Fejes, P. L., Study of the L23 edges in the 3d transition metals and their oxides by electron-energy-loss spectroscopy with comparisons to theory, Phys. Rev. B, 1982, 26: 614-435.[16]Otten, M. T., Buseck, P. R., The oxidation state of Ti in hornblende and biotite determined by electron energy-loss spectroscopy, with inferences regarding the Ti substitution, Phys. Chem. Miner., 1987, 14:45 -51.[17]Sankararaman, M., Perry, D., Valence determination of titanium and iron using electron energy loss spectroscopy, J. Mater. Sci., 1992, 27: 2731-2733.[18]Lusvardi, V. S., Barteau, M. A., Chen, J. G. et al., An NEXAFS investigation of the reduction and reoxidation of TiO2 (001), Surf. Sci., 1998, 397: 237-250.[1]Kingon, A. I., Streiffer, S. K., Basceri, C. et al., High-permittivity perovskite thin films for dynamic random-access memories, MRS Bull., 1996, 21: 46-52.[2]Kingon, A. I., Maria, J. P., Streiffer, S. K., Alternative dielectrics to silicon dioxide for memory and logic devices, Nature (London), 2000, 406: 1032-1038.[3]Stemmer, S., Hoche, T., Keding, R. et al., Oxidation states of titanium in bulk barium titanates and in (100) fiber-textured (BaxSr1- x)Ti1+ yO3+ z thin films, Appl. Phys. Lett., 2001, 79:3149-3151.[4]Stemmer, S., Streiffer, S. K., Browning, N. D. et al., Grain

  8. Preparation of thin vyns films

    International Nuclear Information System (INIS)

    The fabrication of thin films of VYNS resin (copolymer of chloride and vinyl acetate) of superficial density from 3 to 50 μg/cm2 with solutions in cyclohexanone is presented. Study and discussion of some properties compared with formvar film (polyvinyl formals). It appears that both can be used as source supports but formvar films are prepared more easily and more quickly, in addition they withstand higher temperatures. The main quality of VYNS is that they can be easily separated even several days after their preparation

  9. Shielding superconductors with thin films

    CERN Document Server

    Posen, Sam; Catelani, Gianluigi; Liepe, Matthias U; Sethna, James P

    2015-01-01

    Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

  10. Thin Film Solid Lubricant Development

    Science.gov (United States)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  11. Thin film polymeric gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  12. Substrate clamping effect onto magnetoelectric coupling in multiferroic BaTiO3-CoFe2O4 core-shell nanofibers via coaxial electrospinning

    Science.gov (United States)

    Fu, Bi; Lu, Ruie; Gao, Kun; Yang, Yaodong; Wang, Yaping

    2015-10-01

    We report large lateral magnetoelectric (ME) coupling coefficients α 31 of 1.2×104 \\text{mV} \\text{cm}-1 \\text{Oe}-1 and 3.5× 104 \\text{mV} \\text{cm}-1 \\text{Oe}-1 in substrate bonded and free-standing multiferroic BaTiO3-CoFe2O4 (BTO-CFO) core-shell nanofibers (NFs) with and without substrate clamping effect, respectively. The BTO-CFO core-shell NFs were synthesised by a sol-gel coaxial electrospinning technique, and their ME coupling was directly observed by demonstrating the evolution of piezoelectric coefficient (d 33), ferroelectric domain, and phase contrast induced by an external magnetic field. These impressed α 31 coefficients originated from the nanoconfinement of the interphase elastic interaction between the ferromagnetic core fiber and the ferroelectric shell interlayer, as well as the strain transformation at the one-dimensional (1D) fiber boundary. This means that the decreasing substrate clamping effect results in an enhanced ME coupling in multiferroic NFs, which is similar to that of thin films. These findings make people understand the substrate clamping effect and enable nanoscale ME device applications.

  13. Phase Coarsening in Thin Films

    Science.gov (United States)

    Wang, K. G.; Glicksman, M. E.

    2015-08-01

    Phase coarsening (Ostwald ripening) phenomena are ubiquitous in materials growth processes such as thin film formation. The classical theory explaining late-stage phase coarsening phenomena was developed by Lifshitz and Slyozov, and by Wagner in the 1960s. Their theory is valid only for a vanishing volume fraction of the second phase in three dimensions. However, phase coarsening in two-dimensional systems is qualitatively different from that in three dimensions. In this paper, the many-body concept of screening length is reviewed, from which we derive the growth law for a `screened' phase island, and develop diffusion screening theory for phase coarsening in thin films. The coarsening rate constant, maximum size of phase islands in films, and their size distribution function will be derived from diffusion screening theory. A critical comparison will be provided of prior coarsening concepts and improvements derived from screening approaches.

  14. Superfast Thinning of a Nanoscale Thin Liquid Film

    OpenAIRE

    Winkler, Michael; Kofod, Guggi; Krastev, Rumen; Abel, Markus

    2011-01-01

    This fluid dynamics video demonstrates an experiment on superfast thinning of a freestanding thin aqueous film. The production of such films is of fundamental interest for interfacial sciences and the applications in nanoscience. The stable phase of the film is of the order $5-50\\,nm$; nevertheless thermal convection can be established which changes qualitatively the thinning behavior from linear to exponentially fast. The film is thermally driven on one spot by a very cold needle, establishi...

  15. Adsorption property of citrate dispersant on BaTiO3 particles in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    SU Tao-long; ZHUANG Zhi-qiang

    2007-01-01

    Dispersion behavior of ultra fine BaTiO3 particles in the aqueous solution of ammonium citrate (NH4-CA) or citric acid lanthanum chelate (NH4-La-CA) was investigated. The dispersion property was characterized with sedimentation value. It is easier to obtain well dispersed slurry with NH4La-CA than NH4-CA. In an attempt to better understand the role of citric acid radical,simulation of the dispersant adsorption on BaTiO3 particle was performed with universal force field (UFF). It is demonstrated that the interaction between citric acid radical and BaTiO3 particle surface is a weak chemical adsorption. Trivalent citric acid radical is adsorbed on BaTiO3 particle surface with maximal adsorption energy. And, larger molecules of NH4-La-CA formed by adding La3+ lead to better dispersion property than NH4-CA.

  16. Surfactant-assisted synthesis of BaTiO3 nanoparticles by micro-emulsion method

    Directory of Open Access Journals (Sweden)

    J. L. Gao

    2015-10-01

    Full Text Available Barium titanate (BaTiO3 nanoparticles were successfully synthesized by using a surfactant-assisted method. The various processing parameters, namely, th e species of surfactant, reaction temperature and micro-emusion concentration had been varied, and the effects on the micrographs and crystal structure of BaTiO3 particles had been analyzed by scanning electron microscope (SEM, transmission electron microscopy (TEM and X-ray diffraction (XRD. XRD analyses confirming the tetragonal structure of the BaTiO3 nanoparticles using hexadecyl trimethyl ammonium Bromide (CTAB or nonylphenol polyoxyethylene ether (NP-10 as surfactant. The SEM analysis showed that by changing the species of surfactant, grains with different dimensions could be synthesized. TEM analyses indicate that BaTiO3 nanoparticles with 15–20 nm in diameter were successfully synthesized.

  17. Thin films stress modeling : a novel approach

    OpenAIRE

    Bhattacharyya, A. S.; Ramgiri, Praveen Kumar

    2015-01-01

    A novel approach to estimate the thin film stress was discussed based on surface tension. The effect of temperature and film thickness was studies. The effect of stress on the film mechanical properties was observed.

  18. Surfactant-assisted synthesis of BaTiO3 nanoparticles by micro-emulsion method

    OpenAIRE

    Gao, J. L.; Zhi, Y; Ren, X. F.; Liu, Y. H.

    2015-01-01

    Barium titanate (BaTiO3) nanoparticles were successfully synthesized by using a surfactant-assisted method. The various processing parameters, namely, th e species of surfactant, reaction temperature and micro-emusion concentration had been varied, and the effects on the micrographs and crystal structure of BaTiO3 particles had been analyzed by scanning electron microscope (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). XRD analyses confirming the tetragonal structu...

  19. In situ growth BaTiO3 nanocubes and their superlattice from an aqueous process

    Science.gov (United States)

    Dang, Feng; Mimura, Kenichi; Kato, Kazumi; Imai, Hiroaki; Wada, Satoshi; Haneda, Hajime; Kuwabara, Makoto

    2012-02-01

    Ordered aggregated BaTiO3 nanocubes with a narrow size distribution were obtained in an aqueous process by using bis(ammonium lactate) titanium dihydroxide (TALH) as Ti source in the presence of oleic acid and tert-butylamine. Kinetics of the formation of BaTiO3 nanocubes indicated that an in situ growth mechanism was dominant and the superlattice of nanocubes formed in situ through the growth of BaTiO3 nanoparticles in Ti-based hydrous gel. The size and morphology of nanocubes were controlled by tuning the concentration and molar ratio of surfactants. A novel growth model dependant on the structure of Ti precursor for the formation and morphology control of BaTiO3 nanocubes and their superlattice was demonstrated.Ordered aggregated BaTiO3 nanocubes with a narrow size distribution were obtained in an aqueous process by using bis(ammonium lactate) titanium dihydroxide (TALH) as Ti source in the presence of oleic acid and tert-butylamine. Kinetics of the formation of BaTiO3 nanocubes indicated that an in situ growth mechanism was dominant and the superlattice of nanocubes formed in situ through the growth of BaTiO3 nanoparticles in Ti-based hydrous gel. The size and morphology of nanocubes were controlled by tuning the concentration and molar ratio of surfactants. A novel growth model dependant on the structure of Ti precursor for the formation and morphology control of BaTiO3 nanocubes and their superlattice was demonstrated. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11594h

  20. Piezoelectric Properties of BaTiO3 Nanoparticles with Surfaces Modified by Hydroxyl Groups

    Directory of Open Access Journals (Sweden)

    N. Emelianov

    2014-07-01

    Full Text Available Piezoelectric properties of nanoparticles BaTiO3 with spherical shape, diameter of 20-200 nm, the surface-modified hydroxyl (-OH groups studied by piezoelectric force microscopy. Measured value of piezoelectric coefficient d*33  27 pm/V, which is close to the value obtained for the 100 nm particles BaTiO3.

  1. Dispersing and Doping of BaTiO3 Powder by Adsorption

    Institute of Scientific and Technical Information of China (English)

    SU Taolong

    2008-01-01

    Dispersing and doping of BaTiO3 powder by adsorption method were investigated.Ultrafine BaTiO3 powders were dispersed in the aqueous with ammoniumized citrate (NH4-CA) or ammoniumized citric Ianthanum chelate (NH4-La-CA) as dispersant by ultrasonic bath. Better dispersion of BaTiO3 slurry was obtained in the aqueous with NH4-La-CA than that of NH4-CA when the mass ratio of citric acid (CA) to BaTiO3.Was less than 0.007. The pH value hardly affects the dispersion property of BaTiO3 suspension dispersed by NH4-La-CA. BaTiO3 powder could be well dispersed (median size D50=0.45 μm) and also doped with high uniformity of added components by adsorbing citric acid chelate on surface. Compared with solid mixing, better microstructure and properties of La/Mn codoped ceramics were obtained by adsorption method.

  2. Synthesis of BaTiO3 powders by a ball milling-assisted hydrothermal reaction

    International Nuclear Information System (INIS)

    The effects of ball milling during the hydrothermal BaTiO3 synthesis from nano- and sub-micron sized TiO2 powders were studied. The synthesized BaTiO3 powders were characterized by X-ray diffraction (XRD), a laser light scattering particle size distribution analyzer, and field emission scanning electron microscopy (FE-SEM). The XRD patterns showed that BaTiO3 powders could be synthesized using the ball milling system at 100 deg. C and for 5 h with little contamination. The BaTiO3 powders observed by FE-SEM were agglomerated. The agglomerated particle sizes of BaTiO3 prepared from nano- and sub-miron sized TiO2 particles were 152 ± 42 and 148 ± 21 nm, respectively. Furthermore, it was found that the rate constant of BaTiO3 powder prepared from Ba(OH)2 and sub-micrometer sized TiO2 powder with the ball milling process was twice as large compared to a hydrothermal route without ball milling

  3. Probing the Metal-Insulator Transition in BaTiO3 by Electrostatic Doping

    Science.gov (United States)

    Raghavan, Santosh; Zhang, Jack Y.; Shoron, Omor F.; Stemmer, Susanne

    2016-07-01

    The metal-to-insulator transition in BaTiO3 is investigated using electrostatic doping, which avoids effects from disorder and strain that would accompany chemical doping. SmTiO3/BaTiO3/SrTiO3 heterostructures are doped with a constant sheet carrier density of 3 ×1014 cm-2 that is introduced via the polar SmTiO3/BaTiO3 interface. Below a critical BaTiO3 thickness, the structures exhibit metallic behavior with high carrier mobilities at low temperatures, similar to SmTiO3/SrTiO3 interfaces. Above this thickness, data indicate that the BaTiO3 layer becomes ferroelectric. The BaTiO3 lattice parameters increase to a value consistent with a strained, tetragonal unit cell, the structures are insulating below ˜125 K , and the mobility drops by more than an order of magnitude, indicating self-trapping of carriers. The results shed light on the interplay between charge carriers and ferroelectricity.

  4. Plasma polymerized hydrogel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tamirisa, Prabhakar A. [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Koskinen, Jere [Institute of Paper Science and Technology, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Hess, Dennis W. [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)]. E-mail: dennis.hess@chbe.gatech.edu

    2006-12-05

    Plasma polymerization was used to produce thermoresponsive hydrogel films of N-isopropylacrylamide (NIPAAm) in a single deposition step. Solvent free processing to produce laterally confined intelligent hydrogel films offers the potential for high volume production of micro-sensors/actuators. Through variation of reactor conditions such as deposition pressure and substrate temperature, it is possible to tailor and control chemical properties of the films such as crosslink density and thus swelling. Fabrication of hydrogel thin films with adequate crosslinks is critical to ensuring adhesion to substrates and stability in aqueous environments. Chemical bonding structures in plasma polymerized NIPAAm were studied using Fourier transform infrared spectroscopy and the thermoresponsive nature of plasma polymerized NIPAAm was confirmed through contact angle goniometry. A reversible temperature dependent contact angle change was observed.

  5. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States)

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  6. Thin films of soft matter

    CERN Document Server

    Kalliadasis, Serafim

    2007-01-01

    A detailed overview and comprehensive analysis of the main theoretical and experimental advances on free surface thin film and jet flows of soft matter is given. At the theoretical front the book outlines the basic equations and boundary conditions and the derivation of low-dimensional models for the evolution of the free surface. Such models include long-wave expansions and equations of the boundary layer type and are analyzed via linear stability analysis, weakly nonlinear theories and strongly nonlinear analysis including construction of stationary periodic and solitary wave and similarity solutions. At the experimental front a variety of very recent experimental developments is outlined and the link between theory and experiments is illustrated. Such experiments include spreading drops and bubbles, imbibitions, singularity formation at interfaces and experimental characterization of thin films using atomic force microscopy, ellipsometry and contact angle measurements and analysis of patterns using Minkows...

  7. Polycrystalline thin films : A review

    Energy Technology Data Exchange (ETDEWEB)

    Valvoda, V. [Charles Univ., Prague (Czech Republic). Faculty of Mathematics and Physics

    1996-09-01

    Polycrystalline thin films can be described in terms of grain morphology and in terms of their packing by the Thornton`s zone model as a function of temperature of deposition and as a function of energy of deposited atoms. Grain size and preferred grain orientation (texture) can be determined by X-ray diffraction (XRD) methods. A review of XRD analytical methods of texture analysis is given with main attention paid to simple empirical functions used for texture description and for structure analysis by joint texture refinement. To illustrate the methods of detailed structure analysis of thin polycrystalline films, examples of multilayers are used with the aim to show experiments and data evaluation to determine layer thickness, periodicity, interface roughness, lattice spacing, strain and the size of diffraction coherent volumes. The methods of low angle and high angle XRD are described and discussed with respect to their complementary information content.

  8. Structural studies of BaTiO3:Er3+and BaTiO3:Yb3+powders synthesized by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Garrido-Hernndez A; Garca-Murillo A; Carrillo-Romo Fde J; Cruz-Santiago LA; Chadeyron G; Morales-Ramrez Ade J; Velumani S

    2014-01-01

    Erbium and ytterbium doped barium titanate nanopowders were prepared using the hydrothermal method. A barium titan-ate structure doped with rare earth ions manifested new characteristics and improved the field of application of optical devices such as trichromatic tubes, LCD displays, lamps, and infrared lasers. In this work, BaTiO3:Er3+and BaTiO3:Yb3+were prepared using barium chloride [BaCl2], titanium butoxide [C16H36O4Ti], erbium chloride [ErCl3] and ytterbium chloride [YbCl3] as precursors. Anhydrous methanol was employed as a solvent. Metallic potassium was used to promote solubility in the system and increase the pH to 13. This method yielded the formation of a predominantly cubic structure in both Er3+and Yb3+doped BaTiO3 powders. Characteristic bond-ings of BaTiO3 were observed with FT-IR spectroscopy. The predominantly cubic structure was confirmed by X-ray diffraction and micro-Raman analyses. The particle size (∼30 nm) was estimated using the Scherrer equation and X-ray diffraction data. The results were presented and discussed.

  9. Organic thin-film photovoltaics

    OpenAIRE

    Liu, Miaoyin

    2010-01-01

    Zusammenfassung Zur Verbesserung der Leistungsumwandlung in organischen Solarzellen sind neue Materialien von zentraler Bedeutung, die sämtliche Erfordernisse für organische Photovoltaik-Elemente erfüllen. In der vorliegenden Arbeit „Organic thin-film photovoltaics“ wurden im Hinblick auf ein besseres Verständnis der Zusammenhänge zwischen molekularer Struktur und der Leistungsfähigkeit neue Materialien in „bulk-heterojunction“ Solarzellen und in Festphasen-Farbstoffsensibilisierten ...

  10. Photoconductivity of thin organic films

    International Nuclear Information System (INIS)

    Thin organic films were deposited on silicon oxide surfaces with golden interdigitated electrodes (interelectrode gap was 2 μm), and the film resistivities were measured in dark and under white light illumination. The compounds selected for the measurements include molecules widely used in solar cell applications, such as polythiophene (PHT), fullerene (C60), pyrelene tetracarboxylic diimide (PTCDI) and copper phthalocyanine (CuPc), as well as molecules potentially interesting for photovoltaic applications, e.g. porphyrin-fullerene dyads. The films were deposited using thermal evaporation (e.g. for C60 and CuPc films), spin coating for PHT, and Langmuir-Schaeffer for the layer-by-layer deposition of porphyrin-fullerene dyads. The most conducting materials in the series are films of PHT and CuPc with resistivities 1.2 x 103 Ω m and 3 x 104 Ω m, respectively. Under light illumination resistivity of all films decreases, with the strongest light effect observed for PTCDI, for which resistivity decreases by 100 times, from 3.2 x 108 Ω m in dark to 3.1 x 106 Ω m under the light.

  11. Flexible Tactile Sensor Using Polyurethane Thin Film

    OpenAIRE

    Seiji Aoyagi; Tomokazu Takahashi; Masato Suzuki

    2012-01-01

    A novel capacitive tactile sensor using a polyurethane thin film is proposed in this paper. In previous studies, capacitive tactile sensors generally had an air gap between two electrodes in order to enhance the sensitivity. In this study, there is only polyurethane thin film and no air gap between the electrodes. The sensitivity of this sensor is higher than the previous capacitive tactile sensors because the polyurethane is a fairly flexible elastomer and the film is very thin (about 1 µm)....

  12. Thin films for emerging applications v.16

    CERN Document Server

    Francombe, Maurice H

    1992-01-01

    Following in the long-standing tradition of excellence established by this serial, this volume provides a focused look at contemporary applications. High Tc superconducting thin films are discussed in terms of ion beam and sputtering deposition, vacuum evaporation, laser ablation, MOCVD, and other deposition processes in addition to their ultimate applications. Detailed treatment is also given to permanent magnet thin films, lateral diffusion and electromigration in metallic thin films, and fracture and cracking phenomena in thin films adhering to high-elongation substrates.

  13. Minerals deposited as thin films

    International Nuclear Information System (INIS)

    Free matrix effects are due to thin film deposits. Thus, it was decided to investigate this technique as a possibility to use pure oxide of the desired element, extrapolating its concentration from analytical curves made with avoiding, at the same time, mathematical corrections. The proposed method was employed to determine iron and titanium concentrations in geological samples. The range studied was 0.1-5%m/m for titanium and 5-20%m/m for iron. For both elements the reproducibility was about 7% and differences between this method and other chemical determinations were 15% for titanium and 7% for iron. (Author)

  14. Interactions in thin aqueous films

    OpenAIRE

    Hänni-Ciunel, Katarzyna

    2006-01-01

    In der Arbeit werden die Wechselwirkungen in dünnen flüssigen Filmen untersucht und modifiziert. Schaum- (gas/flüssig/gas) und Benetzungsfilme (gas/flüssig/fest) werden mittels Thin Film Pressure Balance (TFPB) untersucht. Die Apparatur wurde im Rahmen der Arbeit für die Studien an asymmetrischen Filmen aufgebaut und modifiziert. Die Ladungen an den Filmgrenzflächen werden gezielt modifiziert. Die Adsoprtion von Tensiden bestimmt die Oberflächenladung an der gas/flüssig Grenzfläche. Die Oberf...

  15. The role of thin films in wetting

    OpenAIRE

    Marmur, Abraham

    1988-01-01

    The role of thin films in wetting is reviewed. Three modes of spontaneous spreading are discussed : incomplete spreading, complete spreading and mixed-mode spreading. A thin film can be either molecular or colloidal in thickness. Molecularly adsorbed films are mainly associated with incomplete spreading. Colloidal films usually extend from the bulk of the liquid in dynamic situations of complete spreading. Their existence at equilibriuim with the bulk depends on the orientation in the gravita...

  16. High-tunability and low-leakage current of the polycrystalline compositionally graded (Ba,Sr)TiO3 thin films derived by a sol-gel process

    International Nuclear Information System (INIS)

    Both up and down compositionally graded Ba1-xSrxTiO3 (BST) thin films with increasing x from 0 to 0.4 were deposited on Si and Pt/Ti/SiO2/Si substrates using sol-gel technique. The microstructure of the graded BST films were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The down graded BST film had a larger dielectric constant and lower dielectric loss than the up graded film. The tunability of the up and down graded BST films was 42.3 and 38.9%, respectively, at an applied field of 250 kV cm-1 and measurement frequency of 1 MHz at room temperature. Both of the graded films had low-leakage current density. While, the leakage current density of down graded film lower two orders than the up graded BST film at the applied electric field below 100 kV cm-1. This may be due to the BaTiO3 layer in the down graded BST film not only serves as a bottom layer but also as an excellent seeding layer to improve the electric properties of the film

  17. Microstructural evolution of tungsten oxide thin films

    International Nuclear Information System (INIS)

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 deg. were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a 'instability wheel' model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  18. Fabrication of BaTiO3 Inverse Opal Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    An XIANG; Jian Ping GAO; Hong Kui CHEN; Jiu Gao YU; Rui Xian LIU

    2004-01-01

    The colloidal crystal template or opal with a closed-packed face centered cubic (fcc) lattice, was prepared from monodisperse polystyrene (PS) spheres by gravity sedimentation. The template was used for the generation of photonic crystal. The template provided void space for infiltration of liquid precursor composed of titanium butyloxide, barium acetate, ethanol, and acetic acid. The opal composite was hydrolyzed, dried, sintered by heating for completely removing PS spheres to form BaTiO3 photonic crystals with inverse opal structure. The PS spheres were replaced by air spheres, which interconnected each other through the windows on the BaTiO3 wall. So both the BaTiO3 wall and air void constitute continuous phases.

  19. Effect of temperature and time on solvothermal synthesis of tetragonal BaTiO3

    Indian Academy of Sciences (India)

    Amir Habib; Nils Stelzer; Paul Angerer; Roland Haubner

    2011-02-01

    Tetragonal BaTiO3 nanoparticles are synthesized via solvothermal route in an ethanol water mixture. Ba(OH)2.8H2O is used as Ba precursor and TiO2 (P25 Degussa ∼25 nm, 30% anatase, 70% rutile) is used as Ti precursor in the Ba : Ti molar ratio 2 : 1. Effect of temperature and time study on solvothermal synthesis of BaTiO3 revealed that a moderate reaction temperature i.e. 185°C and longer reaction time favour tetragonal phase stabilization. Dissolution–precipitation appears to be the transformation mechanism for the crystallization of BaTiO3 from particulate TiO2 precursor.

  20. Grain-size effects on thermal properties of BaTiO3 ceramics

    Indian Academy of Sciences (India)

    C J Xiao; Z X Li; X R Deng

    2011-07-01

    Dense nanocrystalline BaTiO3 ceramics are successfully prepared by the high pressure assisted sintering. Microstructures are observed by scanning electronic microscopes. The grain sizes are estimated to be about 30 and 150 nm. In comparison, BaTiO3 ceramics with the grain size of 600 nm and 1.5 m are fabricated by conventional pressure-less sintering. The thermal properties of BaTiO3 ceramics with different grain sizes are investigated by differential scanning calorimetry and thermal expansion. The results suggest that the enthalpy values for the tetragonal-cubic transition decreased and the thermal expansion values increased with decreasing grain size. Furthermore, the Curie temperature shifts to lower temperature with decreasing grain size.

  1. Effect of Zr on dielectric, ferroelectric and impedance properties of BaTiO3 ceramic

    Indian Academy of Sciences (India)

    Sandeep Mahajan; O P Thakur; Chandra Prakash; K Sreenivas

    2011-12-01

    A polycrystalline sample of Zr-doped barium titanate (BaTiO3) was prepared by conventional solid state reaction method. The effect of Zr (0.15) on the structural and microstructural properties of BaTiO3 was investigated by XRD and SEM. The electrical properties (dielectric, ferroelectric and impedance spectroscopy) were measured in wide range of frequency and temperature. With substitutions of Zr, the structure of BaTiO3 changes from tetragonal to rhombohedral. Lattice parameters were found to increase with substitution. The room temperature dielectric constant increases from ∼ 1675 to ∼ 10586 and peak dielectric constant value increases from ∼ 13626 to ∼ 21023 with diffuse phase transition. Impedance spectroscopy reveals the formation of grain and grain boundary in the material and found to decrease with increase in temperature.

  2. Thin liquid films dewetting and polymer flow

    CERN Document Server

    Blossey, Ralf

    2012-01-01

    This book is a treatise on the thermodynamic and dynamic properties of thin liquid films at solid surfaces and, in particular, their rupture instabilities. For the quantitative study of these phenomena, polymer thin films haven proven to be an invaluable experimental model system.   What is it that makes thin film instabilities special and interesting, warranting a whole book? There are several answers to this. Firstly, thin polymeric films have an important range of applications, and with the increase in the number of technologies available to produce and to study them, this range is likely to expand. An understanding of their instabilities is therefore of practical relevance for the design of such films.   Secondly, thin liquid films are an interdisciplinary research topic. Interdisciplinary research is surely not an end to itself, but in this case it leads to a fairly heterogeneous community of theoretical and experimental physicists, engineers, physical chemists, mathematicians and others working on the...

  3. High quality YBCO superconductive thin films fabricated by laser molecular beam epitaxy

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fan

    2001-01-01

    [1]Hirata,K.,Yamamoto,K.,Iijinma,J.et al.,Tunneling measurements on superconductor/insulator/superconductor junctions using single-crystal YBa2Cu3O7-x thin films,Appl.Phys.Lett.,1990,56(7):683-685.[2]Kingston,J.J.,Wellstood,F.C.,Lerch,P.et al.,Multilayer YBa2Cu3Ox-SrTiO3-YBa2Cu3Ox films for insulating crossovers,Appl.Phys.Lett.,1990,56(2):189-191.[3]Grundler,D.,Krumme,J.P.,David,B.et al.,YBa2Cu3O7 ramp-type junctions and superconducting quantum interference devices with an ultra thin barrier of NdGaO3,Appl.Phys.Lett.,1994,65(14):1841-1843.[4]Yang Guozhen,Lu Huibin,Chen Zhenghao et al.,Laser molecular beam epitaxy system and its key technologies,Science in China (in Chinese),Ser.A,1998,28(3):260-265.[5]Wang Ning,Lu Huibin,Chen,W.Z.et al.,Morphology and microstructure of BaTiO3/SrTiO3 superlattices grown on SrTiO3 by laser molecular-beam epitaxy,Appl.Phys.Lett.,1999,75(22):3464-3466.[6]Chen Li-Chyng,Particulates generated by pulsed laser ablation,in Pulsed Laser Deposition of Thin Films (eds.Chrisey,D.B.,Hulber,G.K.),New York:John Wiley & Sons,Inc.,1994,167-198.[7]Wang,H.S.,Dietsche,W.,Eissler,D.et al.,Molecular beam epitaxial growth and structure properties of DyBa2Cu3O7-y,J.Crys.Growth,1993,126:565-577.[8]Kita,R.,Hase,T.,Itti,R.et al.,Synthesis of CuO films using mass-separated,low-energy O+ ion beams,Appl.Phys.Lett.,1992,60(21):2684-2685.[9]Lu Huibin,Zhou Yueliang,Yang Guozhen et al.,Active gas source for thin film preparation,Chinese Patent (in Chinese),1996,No.ZL 96219046.2.[10]Wang Jing,Chen Fan,Zhao Tong et al.,Fabrication of high stable DC-SQUIDS with L-MBE YBCO thin films,Chinese Journal of Low Temperature Physics (in Chinese),1999,21(1):13-16.

  4. Ellipsometric Studies on Silver Telluride Thin Films

    Directory of Open Access Journals (Sweden)

    M. Pandiaraman

    2011-01-01

    Full Text Available Silver telluride thin films of thickness between 45 nm and 145 nm were thermally evaporated on well cleaned glass substrates at high vacuum better than 10 – 5 mbar. Silver telluride thin films are polycrystalline with monoclinic structure was confirmed by X-ray diffractogram studies. AFM and SEM images of these films are also recorded. The phase ratio and amplitude ratio of these films were recorded in the wavelength range between 300 nm and 700 nm using spectroscopic ellipsometry and analysed to determine its optical band gap, refractive index, extinction coefficient, and dielectric functions. High absorption coefficient determined from the analysis of recorded spectra indicates the presence of direct band transition. The optical band gap of silver telluride thin films is thickness dependent and proportional to square of reciprocal of thickness. The dependence of optical band gap of silver telluride thin films on film thickness has been explained through quantum size effect.

  5. A Novel Process for Synthesis of Ultrafine BaTiO3 Powders

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel process termed low-temperature combustion-synthesis (LCS) of Ba(NO3)-TiO-C6H8O7H2O system was investigated at the initial temperature of 600℃ and ultrafine BaTiO3 powders with a particle size of 200€?350nm were prepared. It was found that the molar ratio of NO/citric acid and the homogeneity of combustion have remarkable effect on the characteristics of the powder. The reaction mechanism of LCS BaTiO3 powders was proposed on the basis of thermodynamic analysis.

  6. Influence of Impurities on the Luminescence of Er3+ Doped BaTiO3 Nanophosphors

    Directory of Open Access Journals (Sweden)

    G. D. Webler

    2014-01-01

    Full Text Available The influence of the presence of barium carbonate (BaCO3 phase on the luminescence properties of barium titanate nanocrystals (BaTiO3 powders was investigated. Structural and optical characterizations of erbium (Er3+ doped BaTiO3 synthesized by the sol-emulsion-gel were performed. Using Fourier transform infrared spectroscopy and X-ray powder diffraction, we identified the presence of impurities related to BaCO3 and quantified its fraction. It was observed that the presence of BaCO3 phase, even at low levels, depletes significantly the infrared-to-visible upconverted luminescence efficiency of the produced nanopowders.

  7. Electrostatic thin film chemical and biological sensor

    Science.gov (United States)

    Prelas, Mark A.; Ghosh, Tushar K.; Tompson, Jr., Robert V.; Viswanath, Dabir; Loyalka, Sudarshan K.

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  8. A study on the damping capacity of BaTiO3-reinforced Al-matrix composites

    Indian Academy of Sciences (India)

    C J XIAO

    2016-04-01

    To study the damping capacity of BaTiO$_3$/Al composites, Al composites reinforced with BaTiO$_3$ powder (average grain sizes: 100 and 1000 nm) were fabricated by the hot-pressing sintering method. The damping properties of pure Al and BaTiO$_3$/Al composites were investigated and compared based on the dynamic mechanical analysis over a wide range of temperatures (50–285$^{\\circ}$C). Compared with pure Al matrix, 1000 nm BaTiO$_3$/Al composites with 5 and 10% mass fractions of BaTiO$_3$ exhibited better damping capacity. For 100 nm BaTiO$_3$/Al composite, its damping capacity is slightly higher than that of pure Al below 145$^{\\circ}$C, while it becomes lower above this degree. The damping capacity enhancement of BaTiO$_3$/Al composites can be explained by the ferroelastic domain damping. Furthermore, 5 and 10% BaTiO$_3$/Al composites have higher bending strength and hardness than pure Al sample.

  9. Nanostructured thin films and coatings functional properties

    CERN Document Server

    Zhang, Sam

    2010-01-01

    The second volume in ""The Handbook of Nanostructured Thin Films and Coatings"" set, this book focuses on functional properties, including optical, electronic, and electrical properties, as well as related devices and applications. It explores the large-scale fabrication of functional thin films with nanoarchitecture via chemical routes, the fabrication and characterization of SiC nanostructured/nanocomposite films, and low-dimensional nanocomposite fabrication and applications. The book also presents the properties of sol-gel-derived nanostructured thin films as well as silicon nanocrystals e

  10. PREPARATION AND CHARACTERIZATION OF POLY-CRYSTALLINE SILICON THIN FILM

    Institute of Scientific and Technical Information of China (English)

    Y.F. Hu; H. Shen; Z.Y. Liu; L.S. Wen

    2003-01-01

    Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells.In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film is discussed. On the film we developed poly-crystalline silicon thin film solar cells with efficiency up to 6. 05% without anti-reflection coating.

  11. Thermal Expansion Coefficients of Thin Crystal Films

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The formulas for atomic displacements and Hamiltonian of a thin crystal film in phonon occupation number representation are obtained with the aid of Green's function theory. On the basis of these results, the formulas for thermal expansion coefficients of the thin crystal film are derived with the perturbation theory, and the numerical calculations are carried out. The results show that the thinner films have larger thermal expansion coefficients.

  12. Slip-controlled thin film dynamics

    OpenAIRE

    Fetzer, R.; Rauscher, M; Münch, A.; Wagner, B. A.; Jacobs, K.

    2006-01-01

    In this study, we present a novel method to assess the slip length and the viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyse dewetting fronts of low molecular weight polystyrene melts on Octadecyl- (OTS) and Dodecyltrichlorosilane (DTS) polymer brushes. Using a thin film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity. We study polymer films with thicknesses between 50 nm and 230 nm and various tempe...

  13. BDS thin film damage competition

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Thomas, M D; Griffin, A J

    2008-10-24

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  14. Thin-film optical shutter

    Science.gov (United States)

    Matlow, S. L.

    1981-02-01

    The ideal solution to the excessive solar gain problem is an optical shutter, a device which switches from being highly transmissive to solar radiation to being highly reflective to solar radiation when a critical temperature is reached in the enclosure. The switching occurs because one or more materials in the device undergo a phase transition at the critical temperature. A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, was chosen as the one most likely to meet all of the requirements of the thin film optical shutter project (TFOS). The reason for this choice is explored. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a quantum mechanical method, the equilibrium bond length (EBL) theory, was developed. Some results of EBL theory are included.

  15. Thin film bioreactors in space

    Science.gov (United States)

    Hughes-Fulford, M.; Scheld, H. W.

    1989-01-01

    Studies from the Skylab, SL-3 and D-1 missions have demonstrated that biological organisms grown in microgravity have changes in basic cellular functions such as DNA, mRNA and protein synthesis, cytoskeleton synthesis, glucose utilization, and cellular differentiation. Since microgravity could affect prokaryotic and eukaryotic cells at a subcellular and molecular level, space offers an opportunity to learn more about basic biological systems with one inmportant variable removed. The thin film bioreactor will facilitate the handling of fluids in microgravity, under constant temperature and will allow multiple samples of cells to be grown with variable conditions. Studies on cell cultures grown in microgravity would make it possible to identify and quantify changes in basic biological function in microgravity which are needed to develop new applications of orbital research and future biotechnology.

  16. Study of the behaviour of the dielectric constant in Cu, Fe: BaTiO3

    Institute of Scientific and Technical Information of China (English)

    Alioune OUEDRAOGO; Kalifa PALM; Issaka OUEDRAOGO; Guy CHANUSSOT

    2008-01-01

    In this work we study the behaviour of the dielectric constant of BaTiO3 single crystals doped with Cu and Fe for different ion percentages, particularly, the influence of these heterovalent substitutions on the ferroelectric-paraelectric phase transition whose temperature is found at Tc=120 ℃ for pure samples. The dielectric constant ε in terms of temperature shows that the Curie temperature decreases when the quantity of impurities increases and presents a broadening and flattering of the maximum of ε(T) within higher values, with the transition becoming more and more diffuse. It is interesting to have a material with very high permittivity (high-k) because of its capacity to store an important quantity of electric charges. The ε anisotropy and the Curie-Weiss law are also verified with a good ratio between the slopes ofε-1(T) from both sides of the transition, leading to a Curie constant: C= 13×104 K for BaTiO3:1.6%Fe in the polar phase. BaTiO3 is a displacive ferroelectric going through a first-order phase transition. The substitutions have an effect on the dynamics of the perovskite lattice. They induce charges transfer to Ti and a diminution of elastic forces in BaTiO3. Then we discuss the fact that the maximum of permittivity does not depend on the phase transition but on the nature of the material.

  17. Magnetization in permalloy thin films

    Indian Academy of Sciences (India)

    Rachana Gupta; Mukul Gupta; Thomas Gutberlet

    2008-11-01

    Thin films of permalloy (Ni80Fe20) were prepared using an Ar+N2 mixture with magnetron sputtering technique at ambient temperature. The film prepared with only Ar gas shows reflections corresponding to the permalloy phase in X-ray diffraction (XRD) pattern. The addition of nitrogen during sputtering results in broadening of the peaks in XRD pattern, which finally leads to an amorphous phase. The - loop for the sample prepared with only Ar gas is matching well with the values obtained for the permalloy. For the samples prepared with increased nitrogen partial pressure the magnetic moment decreased rapidly and the values of coercivity increased. The polarized neutron reflectivity measurements (PNR) were performed in the sample prepared with only Ar gas and with nitrogen partial pressure of 5 and 10%. It was found that the spin-up and spin-down reflectivities show exactly similar reflectivity for the sample prepared with Ar gas alone, while PNR measurements on 5 and 10% sample show splitting in the spin-up and spin-down reflectivity.

  18. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator

    Science.gov (United States)

    Park, Kwi-Il; Bae, Soo Bin; Yang, Seong Ho; Lee, Hyung Ik; Lee, Kisu; Lee, Seung Jun

    2014-07-01

    We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance.We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance. Electronic supplementary information (ESI) available: PDF materials involve the linear superposition test results (Fig. S1) and the durability test results (Fig. S2) of BaTiO3 NWs-based NCG device. A video file (Video S1) shows the power up of an LCD screen by the NCG device without any external energy source. See DOI: 10.1039/c4nr02246g

  19. TiO2 thin film photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YU Jiaguo

    2004-01-01

    It is well known that the photocatalytic activity of TiO2 thin films strongly depends on the preparing methods and post-treatment conditions, since they have a decisive influence on the chemical and physical properties of TiO2 thin films.Therefore, it is necessary to elucidate the influence of the preparation process and post-treatment conditions on the photocatalytic activity and surface microstructures of the films. This review deals with the preparation of TiO2 thin film photocatalysts by wet-chemical methods (such as sol-gel, reverse micellar and liquid phase deposition) and the comparison of various preparation methods as well as their advantage and disadvantage. Furthermore, it is discussed that the advancement of photocatalytic activity, super-hydrophilicity and bactericidal activity of TiO2 thin film photocatalyst in recent years.

  20. Alumina Thin Film Growth: Experiments and Modeling

    OpenAIRE

    Wallin, Erik

    2007-01-01

    The work presented in this thesis deals with experimental and theoretical studies related to the growth of crystalline alumina thin films. Alumina, Al2O3, is a polymorphic material utilized in a variety of applications, e.g., in the form of thin films. Many of the possibilities of alumina, and the problems associated with thin film synthesis of the material, are due to the existence of a range of different crystalline phases. Controlling the formation of the desired phase and the transformati...

  1. Electrochromism of amorphous ruthenium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Se-Hee; Liu, Ping; Tracy, C. Edwin; Deb, Satyen K. [National Renewable Energy Laboratory, Center for Basic Sciences, 1617 Cole Boulevard, Golden, CO 80401 (United States); Cheong, Hyeonsik M. [Sogang University, Shinsoo-Dong, Seoul 121-742 (Korea, Republic of)

    2003-12-01

    We report on the electrochromic behavior of amorphous ruthenium oxide thin films and their electrochemical characteristics for use as counterelectrodes for electrochromic devices. Hydrous ruthenium oxide thin films were prepared by cyclic voltammetry on ITO coated glass substrates from an aqueous ruthenium chloride solution. The cyclic voltammograms of this material show the capacitive behavior including two redox reaction peaks in each cathodic and anodic scan. The ruthenium oxide thin film electrode exhibits a 50% modulation of optical transmittance at 670 nm wavelength with capacitor charge/discharge.

  2. Insect thin films as solar collectors.

    Science.gov (United States)

    Heilman, B D; Miaoulis, L N

    1994-10-01

    A numerical method for simulation of microscale radiation effects in insect thin-film structures is described. Accounting for solar beam and diffuse radiation, the model calculates the reflectivity and emissivity of such structures. A case study examines microscale radiation effects in butterfuly wings, and results reveal a new function of these multilayer thin films: thermal regulation. For film thicknesses of the order of 0.10 µm, solar absorption levels vary by as much as 25% with small changes in film thickness; for certain existing structures, absorption levels reach 96%., This is attributed to the spectral distribution of the reflected radiation, which consists of a singular reflectance peak within the solar spectrum.

  3. Highly stretchable wrinkled gold thin film wires

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joshua, E-mail: joshuk7@uci.edu; Park, Sun-Jun; Nguyen, Thao [Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697 (United States); Chu, Michael [Department of Biomedical Engineering, University of California, Irvine, California 92697 (United States); Pegan, Jonathan D. [Department of Materials and Manufacturing Technology, University of California, Irvine, California 92697 (United States); Khine, Michelle, E-mail: mkhine@uci.edu [Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697 (United States); Department of Biomedical Engineering, University of California, Irvine, California 92697 (United States)

    2016-02-08

    With the growing prominence of wearable electronic technology, there is a need to improve the mechanical reliability of electronics for more demanding applications. Conductive wires represent a vital component present in all electronics. Unlike traditional planar and rigid electronics, these new wearable electrical components must conform to curvilinear surfaces, stretch with the body, and remain unobtrusive and low profile. In this paper, the piezoresistive response of shrink induced wrinkled gold thin films under strain demonstrates robust conductive performance in excess of 200% strain. Importantly, the wrinkled metallic thin films displayed negligible change in resistance of up to 100% strain. The wrinkled metallic wires exhibited consistent performance after repetitive strain. Importantly, these wrinkled thin films are inexpensive to fabricate and are compatible with roll to roll manufacturing processes. We propose that these wrinkled metal thin film wires are an attractive alternative to conventional wires for wearable applications.

  4. Thin films for geothermal sensing: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1987-09-01

    The report discusses progress in three components of the geothermal measurement problem: (1) developing appropriate chemically sensitive thin films; (2) discovering suitably rugged and effective encapsulation schemes; and (3) conducting high temperature, in-situ electrochemical measurements. (ACR)

  5. Electroless plating of thin gold films directly onto silicon nitride thin films and into micropores.

    Science.gov (United States)

    Whelan, Julie C; Karawdeniya, Buddini Iroshika; Bandara, Y M Nuwan D Y; Velleco, Brian D; Masterson, Caitlin M; Dwyer, Jason R

    2014-07-23

    A method to directly electrolessly plate silicon-rich silicon nitride with thin gold films was developed and characterized. Films with thicknesses coating planar, curved, and line-of-sight-obscured silicon nitride surfaces. PMID:24999923

  6. Epitaxy, thin films and superlattices

    International Nuclear Information System (INIS)

    This report is the result of structural investigations of 3d transition metal superlattices consisting of Fe/V, Cr/Mn, V/Mn and Fe/Mn, and a structural and magnetic study of a series of Ho/Pr alloys. The work includes preparation and characterization of substrates as well as growth of thin films and Fe/V superlattices by molecular beam epitaxy, including in-situ characterization by reflection high energy electron diffraction and Auger electron spectroscopy. Structural characterization has been done by x-ray diffraction and neutron diffraction. The x-ray diffraction experiments have been performed on the rotating copper anode at Risoe, and at synchrotron facilities in Hamburg and Brookhaven, and the neutron scattering was done at the Danish research reactor DR3 at Risoe. In addition to longitudinal scans, giving information about the structural parameters in the modulation direction, non-specular scans were also performed. This type of scans gives information about in-plane orientation and lattice parameters. From the analysis, structural information is obtained about lattice parameters, epitaxial strain, coherence lengths and crystallographic orientation for the superlattice systems, except Fe/Mn superlattices, which could not be modelled. For the Ho/Pr alloys, x-ray magnetic scattering was performed, and the crystal and magnetic structure was investigated. (au)

  7. Superconducting thin-film gradiometer

    International Nuclear Information System (INIS)

    We describe the design, fabrication, and performance of planar thin-film dc SQUID's and planar gradiometers in which a dc SQUID is incorporated as a null detector. Each gradiometer was fabricated on a planar substrate and measured an off-diagonal component of changes in the magnetic field gradient. The gradiometer with the highest sensitivity had 127 x 33-mm loops that could be connected in parallel or in series: The sensitivities were 2.1 x 10-13 and 3.7 x 10-13 T m-1 Hz/sup -1/2/, respectively. The intrinsic balance of the gradiometers was about 100 ppm for fields parallel to their plane, and a balance of about 1 ppm could be achieved for fields perpendicular to their plane. When the series-loop gradiometer was rotated through 3600 in the earth's field, the output returned to its initial value to within an amount corresponding to a balance of 1 ppm. Possible improvements in sensitivity are discussed

  8. Synthesis of BaTiO3 powder from barium titanyl oxalate (BTO) precursor employing microwave heating technique

    Indian Academy of Sciences (India)

    Y S Malghe; A V Gurjar; S R Dharwadkar

    2004-06-01

    Cubic barium titanate (BaTiO3) powder was synthesized by heating barium titanyl oxalate hydrate, BaTiO(C2O4)$_{2}\\cdot$4H2O (BTO) precursor in microwave heating system in air at 500°C. Heating BTO in microwave above 600°C yielded tetragonal form of BaTiO3. Experiments repeated in silicon carbide furnace showed that BaTiO3 was formed only above 700°C. The product obtained was cubic.

  9. Thin solid-lubricant films in space

    Science.gov (United States)

    Roberts, E. W.

    Low-friction films of thickness as low as 1 micron, created through sputter-deposition of low shear strength materials, are required in spacecraft applications requiring low power dissipation, such as cryogenic devices, and low torque noise, such as precision-pointing mechanisms. Due to their thinness, these coatings can be applied to high precision-machined tribological components without compromising their functional accuracy. Attention is here given to the cases of thin solid films for ball bearings, gears, and journal bearings.

  10. Laser-annealing of thin semiconductor films

    OpenAIRE

    Boneberg, Johannes; Nedelcu, Johann; Bucher, Ernst; Leiderer, Paul

    1994-01-01

    Optical reflectivity and transmissivity measurements have been used to investigate the dynamics of melting and recrystallisation of thin films of Si and Ge after laser-annealing with a ns Nd:YAG-laser pulse. We report on temperature dependent changes of the reflectivity of the liquid phase above and below the melting point and on various nucleation and solidification scenarios in thin film, depending on the energy density of the amding laser.

  11. Advances in CZTS thin films and nanostructured

    Science.gov (United States)

    Ali, N.; Ahmed, R.; Bakhtiar-Ul-Haq; Shaari, A.

    2015-06-01

    Already published data for the optical band gap (Eg) of thin films and nanostructured copper zinc tin sulphide (CZTS) have been reviewed and combined. The vacuum (physical) and non-vacuum (chemical) processes are focused in the study for band gap comparison. The results are accumulated for thin films and nanostructured in different tables. It is inferred from the re- view that the nanostructured material has plenty of worth by engineering the band gap for capturing the maximum photons from solar spectrum.

  12. Characteristics and durability of fluoropolymer thin films

    OpenAIRE

    Cheneler, David; Bowen, James; Evans, Stephen D.; Górzny, Marcin; Adams, Michael J; Ward, Michael C.L.

    2011-01-01

    The use of plasma-polymerised fluoropolymer (CFxOy) thin films in the manufacture of microelectromechanical systems (MEMS) devices is well-established, being employed in the passivation step of the deep reactive ion etching (DRIE) process, for example. This paper presents an investigation of the effect of exposure to organic and aqueous liquid media on plasma polymerised CFxOy thin films. Atomic force microscopy (AFM), scanning electron microscopy (SEM), ellipsometry, X-ray photoelectron spec...

  13. Microstructural evolution of tungsten oxide thin films

    Science.gov (United States)

    Hembram, K. P. S. S.; Thomas, Rajesh; Rao, G. Mohan

    2009-10-01

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 °C were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a "instability wheel" model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  14. Microstructural evolution of tungsten oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hembram, K.P.S.S., E-mail: hembram@isu.iisc.ernet.in [Department of Instrumentation, Indian Institute of Science, Bangalore - 560 012 (India); Theoretical Science Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064 (India); Thomas, Rajesh; Rao, G. Mohan [Department of Instrumentation, Indian Institute of Science, Bangalore - 560 012 (India)

    2009-10-30

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 deg. were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a 'instability wheel' model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  15. Carbon Nanotube Thin-Film Antennas.

    Science.gov (United States)

    Puchades, Ivan; Rossi, Jamie E; Cress, Cory D; Naglich, Eric; Landi, Brian J

    2016-08-17

    Multiwalled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) dipole antennas have been successfully designed, fabricated, and tested. Antennas of varying lengths were fabricated using flexible bulk MWCNT sheet material and evaluated to confirm the validity of a full-wave antenna design equation. The ∼20× improvement in electrical conductivity provided by chemically doped SWCNT thin films over MWCNT sheets presents an opportunity for the fabrication of thin-film antennas, leading to potentially simplified system integration and optical transparency. The resonance characteristics of a fabricated chlorosulfonic acid-doped SWCNT thin-film antenna demonstrate the feasibility of the technology and indicate that when the sheet resistance of the thin film is >40 ohm/sq no power is absorbed by the antenna and that a sheet resistance of antenna. The dependence of the return loss performance on the SWCNT sheet resistance is consistent with unbalanced metal, metal oxide, and other CNT-based thin-film antennas, and it provides a framework for which other thin-film antennas can be designed.

  16. Thin-film crystalline silicon solar cells

    CERN Document Server

    Brendel, Rolf

    2011-01-01

    This introduction to the physics of silicon solar cells focuses on thin cells, while reviewing and discussing the current status of the important technology. An analysis of the spectral quantum efficiency of thin solar cells is given as well as a full set of analytical models. This is the first comprehensive treatment of light trapping techniques for the enhancement of the optical absorption in thin silicon films.

  17. Bimodal swelling responses in microgel thin films.

    Science.gov (United States)

    Sorrell, Courtney D; Lyon, L Andrew

    2007-04-26

    A series of studies on microgel thin films is described, wherein quartz crystal microgravimetry (QCM), surface plasmon resonance (SPR), and atomic force microscopy (AFM) have been used to probe the properties of microstructured polymer thin films as a function of film architecture and solution pH. Thin films composed of pNIPAm-co-AAc microgels were constructed by using spin-coating layer-by-layer (scLbL) assembly with poly(allylamine hydrochloride) (PAH) as a polycationic "glue". Our findings suggest that the interaction between the negatively charged microgels and the positively charged PAH has a significant impact on the pH responsivity of the film. These effects are observable in both the optical and mechanical behaviors of the films. The most significant changes in behavior are observed when the motional resistance of a quartz oscillator is monitored via QCM experiments. Slight changes to the film architecture and alternating the pH of the environment significantly changes the QCM and SPR responses, suggesting a pH-dependent swelling that is dependent on both particle swelling and polyelectrolyte de-complexation. Together, these studies allow for a deeper understanding of the morphological changes that take place in environmentally responsive microgel-based thin films. PMID:17407344

  18. Post deposition purification of PTCDA thin films

    International Nuclear Information System (INIS)

    The decomposition of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules during evaporation of unpurified raw material in ultra high vacuum was studied. The fragments were identified by mass spectrometry and the influence of these fragments and further contaminations of the raw material on the electronic structure of PTCDA thin films was measured by photoemission spectroscopy. Annealing of contaminated PTCDA films was tested as cheap and easy to perform method for (partial) post deposition purification of the contaminated films

  19. Microcrystalline organic thin-film solar cells.

    Science.gov (United States)

    Verreet, Bregt; Heremans, Paul; Stesmans, Andre; Rand, Barry P

    2013-10-11

    Microcrystalline organic films with tunable thickness are produced directly on an indium-tin-oxide substrate, by crystallizing a thin amorphous rubrene film followed by its use as a template for subsequent homoepitaxial growth. These films, with exciton diffusion lengths exceeding 200 nm, produce solar cells with increasing photocurrents at thicknesses up to 400 nm with a fill factor >65%, demonstrating significant potential for microcrystalline organic electronic devices. PMID:23939936

  20. Electrorheological Particles Composed of PolyanilineCore and BaTiO3 Layer Shell

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Composite particles consisting of polyaniline(PAn) core and barium titanate (BaTiO3) layer shell were synthesized.The PAn-BaTiO3 composites particles were characterized with TEM and XRD.The dielectric behavior of particles was tested and the electrorheological(ER) behavior of the suspensions of PAn/BaTiO3 particles in chlorinated paraffin oil with a 20vol% was investigated under DC electric field.The results show that the ER effect of composite particle is far stronger than that of pure polyaniline and barium titanate which were synthesized by the same method.pH and thickness of BaTiO3 have an important influence on the ER effects.

  1. External field effects on aging phenomenon of acceptor-doped BaTiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Y. Y. Guo

    2015-09-01

    Full Text Available Our experiments on ferroelectric aging phenomena of a series of acceptor-doped BaTiO3 ceramics demonstrate that after well-aging, all samples show a similar double hysteresis loop under smaller applied electric field, regardless of ionic radius or ionic valence of the acceptor. However, with increasing the applied electric field, the completely constricted loops gradually start to open, indicating the aging effect becomes weak under larger electric field. The unified microscopic mechanism responsible for the similar aging behavior in different acceptor-doped BaTiO3 ceramics may be that the larger field is considered to kinetically facilitate a part of oxygen vacancies short-range hopping. As a result, the defect dipole field provided by oxygen vacancies and the associated defect dipoles frozen in the original states decreases, thus contributing to the weaker aging effect.

  2. Ab Initio Calculations for the BaTiO3 (001) Surface Structure

    Institute of Scientific and Technical Information of China (English)

    XUE Xu-Yan; WANG Chun-Lei; ZHONG Wei-Lie

    2004-01-01

    @@ The ab initio method within the local density approximation is applied to calculate cubic BaTiO3 (001) surface relaxation and rumpling for two different terminations (BaO and TiO2). Our calculations demonstrate that cubic perovskite BaTiO3 crystals possess surface polarization, accompanied by the presence of the relevant electric field.We analyse their electronic structures (band structure, density of states and the electronic density redistribution with emphasis on the covalency effects). The results are also compared with that of the previous ab initio calculations. Considerable increases of Ti-O chemical bond covalency nearby the surface have been observed.The band gap reduces especially for the TiO2 termination.

  3. Simulation of iron impurity in BaTiO3 crystals

    International Nuclear Information System (INIS)

    Iron-doped barium titanate (BaTiO3) has been simulated taking into account cubic and tetragonal crystallographic lattices of the crystal. A quantum-chemical method based on the Hartree-Fock formalism has been used throughout the study. The calculated equilibrium structures of Fe-doped crystals reveal the defect-inward displacements of the Ti and O atoms whereas the shifts for the Ba atoms are encountered to be away with respect to the Fe impurity. According to the analysis of electron density population and electron band structure it is found that some unusual chemical bonding might take place between the Fe atom and its six adjacent O atoms. The role of Fe impurity in the ferroelectric polarization of the tetragonal BaTiO3 crystal has been discussed too.

  4. Polymer surfaces, interfaces and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, M. [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany)

    1996-11-01

    Neutron reflectometry can be used in various ways to investigate surfaces, interfaces and thin films of polymers. Its potential comes mostly from the possibilities offered by selective deuteration, where a particular component can be made visible with respect to its activity at the interface. In addition the depth resolution is much better than with most other direct techniques, and details of the profiles may be resolved. Several examples will be discussed including the segment diffusion at the interface between two polymer films, the determination of the narrow interfaces between incompatible polymer blends and the development of order in thin diblock copolymer films. (author) 10 figs., 2 tabs., 38 refs.

  5. Thin-film Rechargeable Lithium Batteries

    Science.gov (United States)

    Dudney, N. J.; Bates, J. B.; Lubben, D.

    1995-06-01

    Thin film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin film battery.

  6. Rupture Limit of Thin Moving Films

    Science.gov (United States)

    Padrino, Juan C.; Joseph, Daniel D.; Kim, Hyungjun

    2010-11-01

    The rupture of a thin film in another fluid is studied including the effects of disjoining pressure. The study considers the linear stability of a moving viscous film in a motionless inviscid fluid and of a stagnant viscous film in a motionless viscous fluid. These are analyzed by means of the Navier--Stokes equations and the dissipation approximation based on potential flow. Results reveal that the dissipation method provides a good approximation for the case of a moving film, whereas its predictions are off the mark for the stagnant film case. The thickness of the gap at the trough of Kelvin-Helmholtz waves locates the formation of holes. The wavelength at final collapse is determined by the length of waves at the trough of the corrugated film. The disjoining pressure effects cause very fast break-up for very thin films. These effects influence the cutoff wavenumber. In the limit of small gaps on this corrugated film, the Reynolds and Weber numbers tend to zero with the gap size, the Ohnesorge number increases like the reciprocal of the square root and the Hamaker number like the reciprocal of the square of the gap. The motion of the film does not enter at the point of formation of holes. Moreover, for the most unstable wave, the ratio of the wavelength to film thickness is found to decrease with decreasing film thickness.

  7. Thin Ice Films at Mineral Surfaces.

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-07-21

    Ice films formed at mineral surfaces are of widespread occurrence in nature and are involved in numerous atmospheric and terrestrial processes. In this study, we studied thin ice films at surfaces of 19 synthetic and natural mineral samples of varied structure and composition. These thin films were formed by sublimation of thicker hexagonal ice overlayers mostly produced by freezing wet pastes of mineral particles at -10 and -50 °C. Vibration spectroscopy revealed that thin ice films contained smaller populations of strongly hydrogen-bonded water molecules than in hexagonal ice and liquid water. Thin ice films at the surfaces of the majority of minerals considered in this work [i.e., metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust] produced intense O-H stretching bands at ∼3400 cm(-1), attenuated bands at ∼3200 cm(-1), and liquid-water-like bending band at ∼1640 cm(-1) irrespective of structure and composition. Illite, a nonexpandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C. As mineral-bound thin ice films are the substrates upon which ice grows from water vapor or aqueous solutions, this study provides new constraints from which their natural occurrences can be understood. PMID:27377606

  8. Structure study of single crystal BaTiO3 nanotube arrays produced by the hydrothermal method

    Science.gov (United States)

    Yang, Yang; Wang, Xiaohui; Sun, Changku; Li, Longtu

    2009-02-01

    High aspect ratio BaTiO3 nanotube arrays with single crystal structure were fabricated by the hydrothermal method at low temperature (150 °C). Numerous structure study methods, including x-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), and x-ray photoelectron spectroscopy (XPS), were used to investigate the structure of single crystal BaTiO3 nanotube arrays. TEM observation shows that BaTiO3 nanotubes have identical crystallographic orientation through their growth directions. EPR and XPS studies show that the obtained BaTiO3 nanotubes contain perceptible oxygen vacancies. Those oxygen vacancies are responsible for the observed green emission band at 545 nm (2.27 eV) detected by photoluminescence study.

  9. Carrier lifetimes in thin-film photovoltaics

    Science.gov (United States)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  10. Magnetoelectric thin film composites with interdigital electrodes

    Science.gov (United States)

    Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knöchel, R.; Quandt, E.

    2013-07-01

    Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

  11. Nanostructured thin films as functional coatings

    Energy Technology Data Exchange (ETDEWEB)

    Lazar, Manoj A; Tadvani, Jalil K; Tung, Wing Sze; Lopez, Lorena; Daoud, Walid A, E-mail: Walid.Daoud@sci.monash.edu.au [School of Applied Sciences and Engineering, Monash University, Churchill, VIC 3842 (Australia)

    2010-06-15

    Nanostructured thin films is one of the highly exploiting research areas particularly in applications such as photovoltaics, photocatalysis and sensor technologies. Highly tuned thin films, in terms of thickness, crystallinity, porosity and optical properties, can be fabricated on different substrates using the sol-gel method, chemical solution deposition (CSD), electrochemical etching, along with other conventional methods such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). The above mentioned properties of these films are usually characterised using surface analysis techniques such as XRD, SEM, TEM, AFM, ellipsometry, electrochemistry, SAXS, reflectance spectroscopy, STM, XPS, SIMS, ESCA, X-ray topography and DOSY-NMR. This article presents a short review of the preparation and characterisation of thin films of nanocrystalline titanium dioxide and modified silicon as well as their application in solar cells, water treatment, water splitting, self cleaning fabrics, sensors, optoelectronic devices and lab on chip systems.

  12. Nanostructured thin films as functional coatings

    International Nuclear Information System (INIS)

    Nanostructured thin films is one of the highly exploiting research areas particularly in applications such as photovoltaics, photocatalysis and sensor technologies. Highly tuned thin films, in terms of thickness, crystallinity, porosity and optical properties, can be fabricated on different substrates using the sol-gel method, chemical solution deposition (CSD), electrochemical etching, along with other conventional methods such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). The above mentioned properties of these films are usually characterised using surface analysis techniques such as XRD, SEM, TEM, AFM, ellipsometry, electrochemistry, SAXS, reflectance spectroscopy, STM, XPS, SIMS, ESCA, X-ray topography and DOSY-NMR. This article presents a short review of the preparation and characterisation of thin films of nanocrystalline titanium dioxide and modified silicon as well as their application in solar cells, water treatment, water splitting, self cleaning fabrics, sensors, optoelectronic devices and lab on chip systems.

  13. Study of the Thin Film Pulse Transformer

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-yuan; SHI Yu; WEN Qi-ye

    2005-01-01

    A new thin film pulse transformer for using in ISND and model systems is fabricated by a mask sputtering process. This novel pulse transformer consists of four I-shaped CoZrRe nanometer crystal magnetic-film cores and a Cu thin film coil, deposited on the micro-crystal glass substrate directly. The thickness of thin film core is between 1 and 3 μm, and the area is between 4mm×6 mm and 12mm×6 mm. The coils provide a relatively high induce of 0.8 μm and can be well operated in a frequency range of 0.001~20 MHz.

  14. Relaxation dynamics of the conductive processes in BaTiO3 ceramics at high temperature

    International Nuclear Information System (INIS)

    The temperature and frequency dependences of the undoped BaTiO3 ceramics dielectric properties were measured between 25 deg. C and 700 deg. C and 100 Hz to 10 MHz, respectively. A dielectric anomaly was observed at low frequencies in the temperature range of 400-700 deg. C. This anomaly was associated to a low frequency dispersion process taking place at high temperature. The relaxation dynamics of the conductive process in BaTiO3 ceramics was investigated. A relaxation function in the time domain (Φ(t)) was determined from the frequency dependence of the dielectric modulus, using a relaxation function in the frequency domain (F*(ω)). In BaTiO3 ceramics context, the best relaxation functions (F*(ω)), in the temperature ranges of 220-400 deg. C and 425 deg. C and 630 deg. C, were found to be a Cole-Cole and Davidson-Cole distribution functions, respectively. The relaxation function (f(t)) obtained by the time domain method was found to be a Kohlrausch-Williams-Watts (KWW) function type. The activation energy values (0.72 eV and 0.8 eV) reveal a mechanism correlated with the movement of single ionized oxygen vacancies and electrons of the second level of ionization, probably due to the formation of a titanium liquid phase during the sintering process.

  15. Effect of fluxing additive on sintering temperature, microstructure and properties of BaTiO3

    Indian Academy of Sciences (India)

    Yaseen Iqbal; Asad Jamal; Riaz Ullah; M Naeem Khan; Rick Ubic

    2012-06-01

    Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0.3wt%Li2CO3 addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO3 was investigated in the present study. The addition of 0.3wt% Li2CO3 was observed to lower the optimum sintering temperature by ∼200°C with no second phase formation and cause a five-fold reduction in grain size. Rhombohedral-to-orthorhombic and tetragonal-to-cubic phase transitions at the expected temperatures were evident from the Raman spectra, but the orthorhombic-totetragonal phase transition was not clearly discernible. The persistence of various phase(s) at higher temperatures in the flux-added materials indicated that the phase transitions occurred relatively slowly. A decrease in dielectric constant of Li2O-added BaTiO3 in comparison to pure BaTiO3 may be due to the diminished dielectric polarizability of Li+ in comparison to Ba2+.

  16. Adjustable character of microwave attenuation in BaTiO3 electrorheological fluids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The behavior of microwave attenuation in BaTiO3 electrorheological fluids is studied when considering microwave propagation in the directions perpendicular and parallel to the particle chains, respectively. In the former case, the microwave attenuation increases with field strength when the particle concentration is low, and the increase of the particle concentration can also increase the microwave attenuation. However, when the particle concentration exceeds a critical value, the attenuation will first increase then decrease with field strength. At the same time, the higher the field strength, the greater the change of microwave attenuation. Moreover, there is a saturation field strength. When the field strength is lower than the saturated one, the change of microwave attenuation is fast. On the other hand, in the case of microwave propagation parallel to the particle chains, the microwave attenuation increases with the field strength monotonously. In addition, the variation of microwave attenuation with the field strength shows relaxation effect. The adjustable character of microwave attenuation in BaTiO3 ER fluids can be attributed to the dielectric changes resulting from the field-induced-structural transformation and the polarization of BaTiO3.

  17. Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

    Science.gov (United States)

    Song, Xiao-lan; He, Xi; Yang, Hai-ping; Qu, Yi-xin; Qiu, Guan-zhou

    2008-06-01

    BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate (Ba(CH3COO)2) and tetra-butyl titanate (Ti(OC4H9)4) as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and transmission electron microscope (TEM). The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

  18. Bismuth ferrite based thin films, nanofibers, and field effect transistor devices

    Science.gov (United States)

    Rivera-Beltran, Rut

    In this research an attempt has been made to explore bismuth ferrite thin films with low leakage current and nanofibers with high photoconductivity. Thin films were deposited with pulsed laser deposition (PLD) method. An attempt has been made to develop thin films under different deposition parameters with following target compositions: i) 0.6BiFeO3-0.4(Bi0.5 K0.5)TiO3 (BFO-BKT) and ii) bi-layered 0.88Bi 0.5Na0.5TiO3-0.08Bi0.5K0.5TiO 3-0.04BaTiO3/BiFeO3 (BNT-BKT-BT/BFO). BFO-BKT thin film shows suppressed leakage current by about four orders of magnitude which in turn improve the ferroelectric and dielectric properties of the films. The optimum remnant polarization is 19 muC.cm-2 at the oxygen partial pressure of 300 mtorr. The BNT-BKT-BT/BFO bi-layered thin films exhibited ferroelectric behavior as: Pr = 22.0 muC.cm-2, Ec = 100 kV.cm-1 and epsilonr = 140. The leakage current of bi-layered thin films have been reduced two orders of magnitude compare to un-doped bismuth ferrite. Bismuth ferrite nanofibers were developed by electrospinning technique and its electronic properties such as photoconductivity and field effect transistor performance were investigated extensively. Nanofibers were deposited by electrospinning of sol-gel solution on SiO2/Si substrate at driving voltage of 10 kV followed by heat treatment at 550 °C for 2 hours. The composition analysis through energy dispersive detector and electron energy loss spectroscopy revealed the heterogeneous nature of the composition with Bi rich and Fe deficient regions. X-ray photoelectron spectroscopy results confirmed the combination of Fe3+ and Fe2+ valence state in the fibers. The photoresponse result is almost hundred times higher for a fiber of 40 nm diameter compared to a fiber with 100 nm diameter. This effect is described by a size dependent surface recombination mechanism. A single and multiple BFO nanofibers field effect transistors devices were fabricated and characterized. Bismuth ferrite FET behaves

  19. Synchrotron Radiation Study on Time-Resolved Tetragonal Lattice Strain of BaTiO3 under Electric Field

    Science.gov (United States)

    Moriyoshi, Chikako; Hiramoto, Shozo; Ohkubo, Hisanori; Kuroiwa, Yoshihiro; Osawa, Hitoshi; Sugimoto, Kunihisa; Kimura, Shigeru; Takata, Masaki; Kitanaka, Yuuki; Noguchi, Yuji; Miyayama, Masaru

    2011-09-01

    The dynamic response of an intrinsic lattice strain in a tetragonal BaTiO3 single crystal to an electric field is investigated. Time-resolved diffraction measurement using high-energy synchrotron radiation enables us to detect the time dependence of the small change in the tetragonality of BaTiO3 during polarization reversal and piezoelectric vibration after a step like electric field antiparallel to the spontaneous polarization is applied to the sample.

  20. Niobium Thin Film Characterization for Thin Film Technology Used in Superconducting Radiofrequency Cavities

    Science.gov (United States)

    Dai, Yishu; Valente-Feliciano, Anne-Marie

    2015-10-01

    Superconducting RadioFrequency (SRF) penetrates about 40-100 nm of the top surface, making thin film technology possible in producing superconducting cavities. Thin film is based on the deposition of a thin Nb layer on top of a good thermal conducting material such as Al or Cu. Thin film allows for better control of the surface and has negligible response to the Earth's magnetic field, eliminating the need for magnetic shielding of the cavities. Thin film superconductivity depends heavily on coating process conditions, involving controllable parameters such as crystal plane orientation, coating temperature, and ion energy. MgO and Al2O3 substrates are used because they offer very smooth surfaces, ideal for studying film growth. Atomic Force Microscopy is used to characterize surface's morphology. It is evident that a lower nucleation energy and a long coating time increases the film quality in the r-plane sapphire crystal orientation. The quality of the film increases with thickness. Nb films coated on r-plane, grow along the (001) plane and yield a much higher RRR compared to the films grown on a- and c-planes. This information allows for further improvement on the research process for thin film technology used in superconducting cavities for the particle accelerators. National Science Foundation, Department of Energy, Jefferson Lab, Old Dominion University.

  1. Electrochemical Analysis of Conducting Polymer Thin Films

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2010-04-01

    Full Text Available Polyelectrolyte multilayers built via the layer-by-layer (LbL method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene (PPV, in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values.

  2. Thermal conductivity of nanoscale thin nickel films

    Institute of Scientific and Technical Information of China (English)

    YUAN Shiping; JIANG Peixue

    2005-01-01

    The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T = 300 K, which is lower than the Debye temperature ()D = 450 K,the results show that in a film thickness range of about 1-11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.

  3. Effect of addition of BaTiO3 nano particles on the electrical transport properties of YBCO superconductor

    Science.gov (United States)

    Rejith, P. P.; Vidya, S.; Thomas, J. K.

    2015-02-01

    The flux pinning properties of YBCO bulk superconductors synthesized by conventional solid state route and are added with different weight% (x=0, 0.5, 1, 2, 3, 5) of nano BaTiO3 which are prepared by a modified combustion route are studied systematically. The phase analysis of the samples was done by using X-ray diffraction and scanning electron microscopy. Temperature-resistivity measurements, magnetic field dependence of critical current density (Jc-B Characteristics) and flux pinning force calculations were done at 77 K. From the SEM images the microstructure of the sample showed a relative uniform distribution of the nano-particles within the specimen. We found that, even though the transition temperature (Tc) does not change considerably with the BaTiO3 addition, both the critical current density (Jc) and flux pinning force (Fp) increased systematically up to 2 wt% BaTiO3 in the composite, in the presence of magnetic field ranging between 0 and 0.6 T. The Jc value in 2 wt% BaTiO3 added sample showed at least 250% larger than that of the pure YBCO. Also the flux pinning force calculated for the 2 wt% BaTiO3 added is found to be enhanced more than 9 times that of pure YBCO. These observations suggest that the BaTiO3 addition to the Y-123- compounds improve the electrical connection between superconducting grains to result in the increase in Jc.

  4. Surface morphology of thin films polyoxadiazoles

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2011-12-01

    Full Text Available urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used. Photos have been taken in noncontact mode while observing an area of 10 x 10 microns.Findings: The analysis of images has confirmed that the quality of thin films depends upon the used polymers. It was also observed that the parameters of the spin coating method have significant effect on the morphology and the surface roughness. The speed of the spin has got a strong impact on the topography of the thin films obtained.Research limitations/implications: The morphology of polyoxadiazoles thin films has been described. This paper include description how the spin speed influences the morphology of polymer thin films. In order to use a polymer thin film in photovoltaics or optoelectronics it must have a uniform thickness and a low surface roughness. Further research, in which the optical properties of thin films are investigated, is strongly recommended.Practical implications: Conductive polymers may find applications in photovoltaics or optoelectronics. It is important to study this group of material engineering and to find a new use for them. Materials from which thin films are made of will have an impact on the properties and characteristics of electronics devices in which they are be applied.Originality/value: The value of this paper is defining the optimal parameters of spin-coating technology for six polyoxadiazoles. The results allow the choosing optimal parameters of the deposition process. Spin coating is a very good method to obtain thin films which

  5. Synthesis of flower-like BaTiO3/Fe3O4 hierarchically structured particles and their electrorheological and magnetic properties.

    Science.gov (United States)

    Wang, Baoxiang; Yin, Yichao; Liu, Chenjie; Yu, Shoushan; Chen, Kezheng

    2013-07-21

    Flower-like BaTiO3/Fe3O4 hierarchically structured particles composed of nano-scale structures on micro-scale materials were synthesized by a simple solvothermal approach and characterized by the means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic testing and rotary viscometer. The influences on the morphology and structure of solvothermal times, type and amount of surfactant, EG : H2O ratio, etc. were studied. Magnetic testing results show that the samples have strong magnetism and they exhibit superparamagnetic behavior, as evidenced by no coercivity and the remanence at room temperature, due to their very small sizes, observed on the M-H loop. The saturation magnetization (M(s)) value can achieve 18.3 emu g(-1). The electrorheological (ER) effect was investigated using a suspension of the flower-like BaTiO3/Fe3O4 hierarchically structured particles dispersed in silicone oil. We can observe a slight shear-thinning behavior of shear viscosity at a low shear rate region even at zero applied electric field and a Newtonian fluid behavior at high shear rate regions. PMID:23714846

  6. Thin Films in the Photovoltaic Industry

    International Nuclear Information System (INIS)

    In the past years, the yearly world market growth rate for Photovoltaics was an average of more than 40%, which makes it one of the fastest growing industries at present. Business analysts predict the market volume to increase to 40 billion euros in 2010 and expect rising profit margins and lower prices for consumers at the same time. Today PV is still dominated by wafer based Crystalline Silicon Technology as the 'working horse' in the global market, but thin films are gaining market shares. For 2007 around 12% are expected. The current silicon shortage and high demand has kept prices higher than anticipated from the learning curve experience and has widened the windows of opportunities for thin film solar modules. Current production capacity estimates for thin films vary between 3 and 6 GW in 2010, representing a 20% market share for these technologies. Despite the higher growth rates for thin film technologies compared with the industry average, Thin Film Photovoltaic Technologies are still facing a number of challenges to maintain this growth and increase market shares. The four main topics which were discussed during the workshop were: Potential for cost reduction; Standardization; Recycling; Performance over the lifetime.

  7. Thin film calorimetry of polymer films

    Science.gov (United States)

    Zhang, Wenhua; Rafailovich, Miriam; Sokolov, Jonathan; Salamon, William

    2000-03-01

    Polystryene and polymethylmethacrylate films for thicknesses ranging from 50nm to 500nm using a direct calorimetric technique (Lai et al, App. Phys. Lett. 67, p9(1995)). Samples were deposited on Ni foils(2-2.5um) and placed in a high vacuum oven. Calibrated heat pulses were input to the polymer films by current pulses to the Ni substrate and temperature changes were determined from the change in Ni resistance. Pulses producing temperature jumps of 3-8K were used and signal averaging over pulses reduced noise levels enough to identify glass transitions down to 50nm. Molecular weight dependence of thick films Tg was used as a temperature calibration.

  8. Magnetic and electrical properties on possible room temperature hybrid multiferroic BaTiO3/La2/3Sr1/3MnO3

    Science.gov (United States)

    Ordoñez, John Edward; Gómez, María Elena; Lopera Muñoz, Wilson; Prieto, Pedro Antonio; Thin Film Group Team; Center of Excellence on Novel Materials-CENM, Cali, Colombia Team

    2015-03-01

    We addressed to deposit the ferromagnetic phase of the La1-xSrxMnO3 and the ferroelectric BaTiO3 for possible hybrid multiferroic heterostructure. We have optimized the growth parameters for depositing BaTiO3(BTO) / La2/3Ca1/3MnO3(LCMO) / (001) SrTiO3 by sputtering RF and DC, respectively, in pure oxygen atmosphere and a substrate temperature of 830°C. Keeping fixed the magnetic layer thickness (tLSMO = 40 nm) and varying the thickness of the ferroelectric layer (tBTO = 20, 40, 80, 100 nm). We want to point out the influence of the thicknesses ratio (tBTO/tLSMO) on electrical and magnetic properties. From x-ray diffraction (XRD) analysis, we found the bragg peaks for LSMO maintain its position but BTO peak shift to lower Bragg angle indicating a strained BTO film. Magnetization and polarization measurements indicate a possible multiferroic behavior in the bilayers. Hysteresis loop measurements of bilayers show ferromagnetic behavior. Authors thank Instituto de Nanociencia de Aragón, Zaragoza, Spain. Work partially supported by COLCIENCIAS-UNIVALLE Project 110656933104 Contract No. 2013-0002, CI 7917 and CI 7978.

  9. Organic thin films and surfaces directions for the nineties

    CERN Document Server

    Ulman, Abraham

    1995-01-01

    Physics of Thin Films has been one of the longest running continuing series in thin film science consisting of 20 volumes since 1963. The series contains some of the highest quality studies of the properties ofvarious thin films materials and systems.In order to be able to reflect the development of todays science and to cover all modern aspects of thin films, the series, beginning with Volume 20, will move beyond the basic physics of thin films. It will address the most important aspects of both inorganic and organic thin films, in both their theoretical as well as technological aspects. Ther

  10. Crystallization of zirconia based thin films.

    Science.gov (United States)

    Stender, D; Frison, R; Conder, K; Rupp, J L M; Scherrer, B; Martynczuk, J M; Gauckler, L J; Schneider, C W; Lippert, T; Wokaun, A

    2015-07-28

    The crystallization kinetics of amorphous 3 and 8 mol% yttria stabilized zirconia (3YSZ and 8YSZ) thin films grown by pulsed laser deposition (PLD), spray pyrolysis and dc-magnetron sputtering are explored. The deposited films were heat treated up to 1000 °C ex situ and in situ in an X-ray diffractometer. A minimum temperature of 275 °C was determined at which as-deposited amorphous PLD grown 3YSZ films fully crystallize within five hours. Above 325 °C these films transform nearly instantaneously with a high degree of micro-strain when crystallized below 500 °C. In these films the t'' phase crystallizes which transforms at T > 600 °C to the t' phase upon relaxation of the micro-strain. Furthermore, the crystallization of 8YSZ thin films grown by PLD, spray pyrolysis and dc-sputtering are characterized by in situ XRD measurements. At a constant heating rate of 2.4 K min(-1) crystallization is accomplished after reaching 800 °C, while PLD grown thin films were completely crystallized already at ca. 300 °C. PMID:26119755

  11. Solid surfaces, interfaces and thin films

    CERN Document Server

    Lüth, Hans

    2015-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin-film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological structure, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure research, particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures. A special chapter of the book is devoted to collective phenomena at interfaces and in thin films such as superconductivity and magnetism. The latter topic includes the meanwhile important issues giant magnetoresistance and spin-transfer torque mechanism, both effects being of high interest in information technology. In this new edition, for the first time, the effect of spin-orbit coupling on surface states is treated. In this context the class of the recently detected topological insulators,...

  12. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  13. Thin Film Photovoltaic/Thermal Solar Panels

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2008-01-01

    A solar panel is described.in which thin films of semiconductor are deposited onto a metal substrate.The semiconductor-metal combination forms a thin film photovoltaic cell,and also acts as a reflector,absorber tandem, which acts as a solar selective surface,thus enhancing the solar thermal performance of the collector plate.The use of thin films reduces the distance heat is required to flow from the absorbing surface to the metal plate and heat exchange conduits.Computer modelling demonstrated that,by suitable choice of materials,photovohaic efficiency call be maintained,with thermal performance slishtly reduced,compared to that for thermal-only panels.By grading the absorber layer-to reduce the band gap in the lower region-the thermal performance can be improved,approaching that for a thermal-only solar panel.

  14. Thin-film solar cells. Duennschichtsolarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Bloss, W.H.; Pfisterer, F.; Schock, H.W. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Physikalische Elektronik)

    1990-01-01

    The authors present the state of the art in research and development, technology, production and marketing, and of the prospects of thin-film solar cells. Thin-film solar cells most used at present are based on amorphous silicon and on the compound semiconductors CuInSe{sub 2} and CdTe. Efficiencies in excess 12% have been achieved (14.1% with CuInSe{sub 2}). Stability is the main problem with amorphous silicon. Thin-film solar cells made from compound semiconductors do not have this problem, though their cost-effective series production needs to be shown still. The development potential of the three types mentioned will be ca. 30% in terms of efficiency: in terms of production cost, it is estimated with some certainty to be able to reach the baseline of 1 DM/Watt peak output (W{sub p}). (orig.).

  15. Vibration welding system with thin film sensor

    Science.gov (United States)

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  16. Method for synthesizing thin film electrodes

    Science.gov (United States)

    Boyle, Timothy J.

    2007-03-13

    A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

  17. Solid Surfaces, Interfaces and Thin Films

    CERN Document Server

    Lüth, Hans

    2010-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure physics particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures as well as to superconductor/semiconductor interfaces and magnetic thin films. The latter topic was significantly extended in this new edition by more details about the giant magnetoresistance and a section about the spin-transfer torque mechanism including one new problem as exercise. Two new panels about Kerr-effect and spin-polarized scanning tunnelling microscopy were added, too. Furthermore, the meanwhile important group III-nitride surfaces and high-k oxide/semiconductor interfaces are shortly discu...

  18. Capillary instabilities in thin films. I. Energetics

    Energy Technology Data Exchange (ETDEWEB)

    Srolovitz, D.J.; Safran, S.A.

    1986-07-01

    A stability theory is presented which describes the conditions under which thin films rupture. It is found that holes in the film will either grow or shrink, depending on whether their initial radius is larger or smaller than a critical value. If the holes grow large enough, they impinge to form islands; the size of which are determined by the surface energies. The formation of grooves where the grain boundary meets the free surface is a potential source of holes which can lead to film rupture. Equilibrium grain boundary groove depths are calculated for finite grain sizes. Comparison of groove depth and film thickness yields microstructural conditions for film rupture. In addition, pits which form at grain boundary vertices, where three grains meet, are another source of film instability.

  19. Thin film oxygen partial pressure sensor

    Science.gov (United States)

    Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

    1972-01-01

    The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

  20. Tailoring electronic structure of polyazomethines thin films

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2010-09-01

    Full Text Available Purpose: The aim of this work is to show how electronic properties of polyazomethine thin films deposited by chemical vapor deposition method (CVD can be tailored by manipulating technological parameters of pristine films preparation as well as modifying them while the as-prepared films put into iodine atmosphere.Design/methodology/approach: The recent achievements in the field of designing and preparation methods to be used while preparing polymer photovoltaic solar cells or optoelectronic devices.Findings: The method used allow for pure pristine polymer thin films to be prtepared without any unintentional doping taking place during prepoaration methods. This is a method based on polycondensation process, where polymer chain developing is running directly due to chemical reaction between molecules of bifunctional monomers. The method applied to prepare thin films of polyazomethines takes advantage of monomer transporting by mreans of neutral transport agent as pure argon is.Research limitations/implications: The main disadvantage of alternately conjugated polymers seems to be quite low mobility of charge carrier that is expected to be a consequence of their backbone being built up of sp2 hybridized carbon and nitrogen atoms. Varying technological conditions towards increasing reagents mass transport to the substrate is expected to give such polyazomethine thin films organization that phenylene rin stacking can result in special π electron systems rather than linear ones as it is the case.Originality/value: Our results supply with original possibilities which can be useful in ooking for good polymer materials for optoelectronic and photovoltaic applications. These results have been gained on polyazomethine thin films but their being isoelectronic counterpart to widely used poly p-phenylene vinylene may be very convenient to develop high efficiency polymer solar cells

  1. Large reversible caloric effect in FeRh thin films via a dual-stimulus multicaloric cycle

    Science.gov (United States)

    Liu, Yang; Phillips, Lee C.; Mattana, Richard; Bibes, Manuel; Barthélémy, Agnès; Dkhil, Brahim

    2016-05-01

    Giant magnetocaloric materials are promising for solid-state refrigeration, as an alternative to hazardous gases used in conventional cooling devices. A giant magnetocaloric effect was discovered near room temperature in near-equiatomic FeRh alloys some years before the benchmark study in Gd5Si2Ge2 that launched the field. However, FeRh has attracted significantly less interest in cooling applications mainly due to irreversibility in magnetocaloric cycles associated with the large hysteresis of its first-order metamagnetic phase transition. Here we overcome the irreversibility via a dual-stimulus magnetic-electric refrigeration cycle in FeRh thin films via coupling to a ferroelectric BaTiO3 substrate. This experimental realization of a multicaloric cycle yields larger reversible caloric effects than either stimulus alone. While magnetic hysteretic losses appear to be reduced by 96% in dual-stimulus loops, we show that the losses are simply transferred into an elastic cycle, contrary to common belief. Nevertheless, we show that these losses do not necessarily prohibit integration of FeRh in practical refrigeration systems. Our demonstration of a multicaloric refrigeration cycle suggests numerous designs for efficient solid-state cooling applications.

  2. Advances in thin-film solar cells

    CERN Document Server

    Dharmadasa, I M

    2012-01-01

    This book concentrates on the latest developments in our understanding of solid-state device physics. The material presented is mainly experimental and based on CdTe thin-film solar cells. It extends these new findings to CIGS thin-film solar cells and presents a new device design based on graded bandgap multilayer solar cells. This design has been experimentally tested using the well-researched GaAs/AlGaAs system and initial devices have shown impressive device parameters. These devices are capable of absorbing all radiation (UV, visible, and infra-red) within the solar spectrum and combines

  3. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin; Christiansen, N.O.;

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity...... and strain sensitivity using two- and four-point measurement method. We have found that polyaniline has a negative gauge factor of K = -4.9, which makes it a candidate for piezoresistive read-out in polymer based MEMS-devices. (C) 2007 Elsevier B.V. All rights reserved....

  4. Thin Films Made Fast and Modified Fast

    International Nuclear Information System (INIS)

    Thin films are playing a more and more important role for technological applications and there are many aspects of materials surface processing and thin film production, ranging from simple heat treatments to ion implantation or laser surface treatments. These methods are often very complicated, involving many basic processes and they have to be optimized for the desired application. Nuclear methods, especially Moessbauer spectroscopy, can be successfully applied for this task and some examples will be presented for laser-beam and ion-beam based processes.

  5. Feasibility Study of Thin Film Thermocouple Piles

    Science.gov (United States)

    Sisk, R. C.

    2001-01-01

    Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

  6. Electrical analysis of niobium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Graça, M.P.F., E-mail: mpfg@ua.pt [I3N & Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Saraiva, M. [I3N & Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Freire, F.N.A. [Mechanics Engineering Department, Ceará Federal University, Fortaleza (Brazil); Valente, M.A.; Costa, L.C. [I3N & Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal)

    2015-06-30

    In this work, a series of niobium oxide thin films was deposited by reactive magnetron sputtering. The total pressure of Ar/O{sub 2} was kept constant at 1 Pa, while the O{sub 2} partial pressure was varied up to 0.2 Pa. The depositions were performed in a grounded and non-intentionally heated substrate, resulting in as-deposited amorphous thin films. Raman spectroscopy confirmed the absence of crystallinity. Dielectric measurements as a function of frequency (40 Hz–110 MHz) and temperature (100 K–360 K) were performed. The dielectric constant for the film samples with thickness (d) lower than 650 nm decreases with the decrease of d. The same behaviour was observed for the conductivity. These results show a dependence of the dielectric permittivity with the thin film thickness. The electrical behaviour was also related with the oxygen partial pressure, whose increment promotes an increase of the Nb{sub 2}O{sub 5} stoichiometry units. - Highlights: • Niobium oxide thin films were deposited by reactive magnetron sputtering. • XRD showed a phase change with the increase of the P(O{sub 2}). • Raman showed that increasing P(O{sub 2}), Nb{sub 2}O{sub 5} amorphous increases. • Conductivity tends to decrease with the increase of P(O{sub 2}). • Dielectric analysis indicates the inexistence of preferential grow direction.

  7. Electrical analysis of niobium oxide thin films

    International Nuclear Information System (INIS)

    In this work, a series of niobium oxide thin films was deposited by reactive magnetron sputtering. The total pressure of Ar/O2 was kept constant at 1 Pa, while the O2 partial pressure was varied up to 0.2 Pa. The depositions were performed in a grounded and non-intentionally heated substrate, resulting in as-deposited amorphous thin films. Raman spectroscopy confirmed the absence of crystallinity. Dielectric measurements as a function of frequency (40 Hz–110 MHz) and temperature (100 K–360 K) were performed. The dielectric constant for the film samples with thickness (d) lower than 650 nm decreases with the decrease of d. The same behaviour was observed for the conductivity. These results show a dependence of the dielectric permittivity with the thin film thickness. The electrical behaviour was also related with the oxygen partial pressure, whose increment promotes an increase of the Nb2O5 stoichiometry units. - Highlights: • Niobium oxide thin films were deposited by reactive magnetron sputtering. • XRD showed a phase change with the increase of the P(O2). • Raman showed that increasing P(O2), Nb2O5 amorphous increases. • Conductivity tends to decrease with the increase of P(O2). • Dielectric analysis indicates the inexistence of preferential grow direction

  8. Dynamics of liquid films and thin jets

    Science.gov (United States)

    Zak, M.

    1979-01-01

    The theory of liquid films and thin jets as one- and two-dimensional continuums is examined. The equations of motion have led to solutions for the characteristic speeds of wave propagation for the parameters characterizing the shape. The formal analogy with a compressible fluid indicates the possibility of shock wave generation in films and jets and the formal analogy to the theory of threads and membranes leads to the discovery of some new dynamic effects. The theory is illustrated by examples.

  9. Viscous fingering in volatile thin films

    OpenAIRE

    Agam, Oded

    2008-01-01

    A thin water film on a cleaved mica substrate undergoes a first order phase transition between two values of film thickness. By inducing a finite evaporation rate of the water, the interface between the two phases develops a fingering instability similar to that observed in the Saffman-Taylor problem. We draw the connection between the two problems, and construct solutions describing the dynamics of evaporation in this system.

  10. Thin film dynamics with surfactant phase transition

    OpenAIRE

    Köpf, M. H.; Gurevich, S. V.; Friedrich, R.

    2009-01-01

    A thin liquid film covered with an insoluble surfactant in the vicinity of a first-order phase transition is discussed. Within the lubrication approximation we derive two coupled equations to describe the height profile of the film and the surfactant density. Thermodynamics of the surfactant is incorporated via a Cahn-Hilliard type free-energy functional which can be chosen to describe a transition between two stable phases of different surfactant density. Within this model, a linear stabilit...

  11. Perovskite thin films via atomic layer deposition.

    Science.gov (United States)

    Sutherland, Brandon R; Hoogland, Sjoerd; Adachi, Michael M; Kanjanaboos, Pongsakorn; Wong, Chris T O; McDowell, Jeffrey J; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J; Sargent, Edward H

    2015-01-01

    A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3 NH3 PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm(-1) .

  12. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  13. Factors influencing formation of highly dispersed BaTiO3 nanospheres with uniform sizes in static hydrothermal synthesis

    International Nuclear Information System (INIS)

    Highly dispersed BaTiO3 nanospheres with uniform sizes have important applications in micro/nanoscale functional devices. To achieve well-dispersed spherical BaTiO3 nanocrystals, we carried out as reported in this paper the systematic investigation on the factors that influence the formation of BaTiO3 nanospheres by the static hydrothermal process, including the NaOH concentrations [NaOH], molar Ba/Ti ratios (RBa/Ti), hydrothermal temperatures, and durations, with an emphasis on understanding the related mechanisms. Barium nitrate and TiO2 sols derived from tetrabutyl titanate were used as the starting materials. The as-synthesized BaTiO3 samples were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetry, differential thermal analysis, and FT-IR spectra. The highly dispersed BaTiO3 nanospheres (76 ± 13 nm) were achieved under the optimum hydrothermal conditions at 200 °C for 10 h: [NaOH] = 2.0 mol L−1 and RBa/Ti = 1.5. Higher NaOH concentrations, higher Ba/Ti ratios, higher hydrothermal temperatures, and longer hydrothermal durations are favorable in forming BaTiO3 nanospheres with larger fractions of tetragonal phase and higher yields; but too long hydrothermal durations resulted in abnormal growth and reduced the uniformity in particle sizes. The possible formation mechanisms for BaTiO3 nanocrystals under the static hydrothermal conditions were investigated

  14. YBCO thin films in ac and dc films

    CERN Document Server

    Shahzada, S

    2001-01-01

    We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)

  15. Energetic Deposition of Niobium Thin Film in Vacuum

    OpenAIRE

    Wu, Genfa

    2002-01-01

    Niobium thin films are expected to be free of solid inclusions commonly seen in solid niobium. For particle accelerators, niobium thin film has the potential to replace the solid niobium in the making of the accelerating structures. In order to understand and improve the superconducting performance of niobium thin films at cryogenic temperature, an energetic vacuum deposition system has been developed to study deposition energy effects on the properties of niobium thin films on various substr...

  16. Correlated dewetting patterns in thin polystyrene films

    International Nuclear Information System (INIS)

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes

  17. Correlated dewetting patterns in thin polystyrene films

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes.

  18. Humidity sensing characteristics of hydrotungstite thin films

    Indian Academy of Sciences (India)

    G V Kunte; S A Shivashankar; A M Umarji

    2008-11-01

    Thin films of the hydrated phase of tungsten oxide, hydrotungstite (H2WO4.H2O), have been grown on glass substrates using a dip-coating technique. The -axis oriented films have been characterized by X-ray diffraction and scanning electron microscopy. The electrical conductivity of the films is observed to vary with humidity and selectively show high sensitivity to moisture at room temperature. In order to understand the mechanism of sensing, the films were examined by X-ray diffraction at elevated temperatures and in controlled atmospheres. Based on these observations and on conductivity measurements, a novel sensing mechanism based on protonic conduction within the surface layers adsorbed onto the hydrotungstite film is proposed.

  19. Tailored piezoelectric thin films for energy harvester

    NARCIS (Netherlands)

    Wan, X.

    2013-01-01

    Piezoelectric materials are excellent materials to transfer mechanical energy into electrical energy, which can be stored and used to power other devices. PiezoMEMS is a good way to combine silicon wafer processing and piezoelectric thin film technology and lead to a variety of miniaturized and prem

  20. New techniques for producing thin boron films

    International Nuclear Information System (INIS)

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs

  1. Flexoelectricity in barium strontium titanate thin film

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning, E-mail: xjiang5@ncsu.edu [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Shu, Longlong [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Electronic Materials Research Laboratory, International Center for Dielectric Research, Xi' an Jiao Tong University, Xi' an, Shaanxi 710049 (China); Maria, Jon-Paul [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-10-06

    Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 μC/m at Curie temperature (∼28 °C) and 17.44 μC/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10–100 μC/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.

  2. US Polycrystalline Thin Film Solar Cells Program

    Science.gov (United States)

    Ullal, Harin S.; Zweibel, Kenneth; Mitchell, Richard L.

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R and D on copper indium diselenide and cadmium telluride thin films. The objective of the program is to support research to develop cells and modules that meet the U.S. Department of Energy's long-term goals by achieving high efficiencies (15 to 20 percent), low-cost ($50/m(sup 2)), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe2 and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The U.S. Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe2 and CdTe with subcontracts to start in spring 1990.

  3. US polycrystalline thin film solar cells program

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H S; Zweibel, K; Mitchell, R L [Solar Energy Research Inst., Golden, CO (USA)

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R D on copper indium diselenide and cadmium telluride thin films. The objective of the Program is to support research to develop cells and modules that meet the US Department of Energy's long-term goals by achieving high efficiencies (15%-20%), low-cost ($50/m{sup 2}), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The US Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe{sub 2} and CdTe with subcontracts to start in Spring 1990. 23 refs., 5 figs.

  4. Incipient plasticity in metallic thin films

    NARCIS (Netherlands)

    Soer, W. A.; De Hosson, J. Th. M.; Minor, A. M.; Shan, Z.; Asif, S. A. Syed; Warren, O. L.

    2007-01-01

    The authors have compared the incipient plastic behaviors of Al and Al-Mg thin films during indentation under load control and displacement control. In Al-Mg, solute pinning limits the ability of dislocations to propagate into the crystal and thus substantially affects the appearance of plastic inst

  5. Rechargeable Thin-film Lithium Batteries

    Science.gov (United States)

    Bates, J. B.; Gruzalski, G. R.; Dudney, N. J.; Luck, C. F.; Yu, Xiaohua

    1993-08-01

    Rechargeable thin film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have recently been developed. The batteries, which are typically less than 6 {mu}m thick, can be fabricated to any specified size, large or small, onto a variety of substrates including ceramics, semiconductors, and plastics. The cells that have been investigated include Li TiS{sub 2}, Li V{sub 2}O{sub 5}, and Li Li{sub x}Mn{sub 2}O{sub 4}, with open circuit voltages at full charge of about 2.5, 3.6, and 4.2, respectively. The development of these batteries would not have been possible without the discovery of a new thin film lithium electrolyte, lithium phosphorus oxynitride, that is stable in contact with metallic lithium at these potentials. Deposited by rf magnetron sputtering of Li{sub 3}PO{sub 4} in N{sub 2}, this material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25{degrees}C of 2 {mu}S/cm. The maximum practical current density obtained from the thin film cells is limited to about 100 {mu}A/cm{sup 2} due to a low diffusivity of Li{sup +} ions in the cathodes. In this work, the authors present a short review of their work on rechargeable thin film lithium batteries.

  6. A ferroelectric transparent thin-film transistor

    NARCIS (Netherlands)

    Prins, MWJ; GrosseHolz, KO; Muller, G; Cillessen, JFM; Giesbers, JB; Weening, RP; Wolf, RM

    1996-01-01

    Operation is demonstrated of a field-effect transistor made of transparant oxidic thin films, showing an intrinsic memory function due to the usage of a ferroelectric insulator. The device consists of a high mobility Sb-doped n-type SnO2 semiconductor layer, PbZr0.2Ti0.8Os3 as a ferroelectric insula

  7. Electrical characterization of thin film ferroelectric capacitors

    NARCIS (Netherlands)

    Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D.; Keur, W.; Schmitz, J.; Hueting, R.J.E.

    2006-01-01

    Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offe

  8. Resistance contact thin-film resistor

    Directory of Open Access Journals (Sweden)

    Spirin V. G.

    2008-10-01

    Full Text Available The analytical model of the calculation of the contact resistance of the thin-film resistor is Offered. The Explored dependency of the contact resistance from wedge of the pickling. The Considered influence adhesive layer on warm-up stability of the resistor. They Are Received formulas of the calculation systematic and casual inaccuracy contributed by contact resistance.

  9. Stabilized thin film heterostructure for electrochemical applications

    DEFF Research Database (Denmark)

    2015-01-01

    The invention provides a method for the formation of a thin film multi-layered heterostructure upon a substrate, said method comprising the steps of: a. providing a substrate; b. depositing a buffer layer upon said substrate, said buffer layer being a layer of stable ionic conductor (B); c. depos...

  10. Electrostatic Discharge Effects in Thin Film Transistors

    NARCIS (Netherlands)

    Golo, Natasa

    2002-01-01

    Although amorphous silicon thin film transistors (α-Si:H TFT’s) have a very low electron mobility and pronounced instabilities of their electrical characteristics, they are still very useful and they have found their place in the semiconductors industry, as they possess some very good properties: th

  11. Reliability growth of thin film resistors contact

    Directory of Open Access Journals (Sweden)

    Lugin A. N.

    2010-10-01

    Full Text Available Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

  12. Polarization Fatigue in Ferroelectric Thin Films

    Institute of Scientific and Technical Information of China (English)

    王忆; K.H.WONG; 吴文彬

    2002-01-01

    The fatigue problem in ferroelectric thin films is investigated based on the switched charge per unit area versus switching cycles. The temperature, dielectric permittivity, voltage bias, frequency and defect valence dependent switching polarization properties are calculated quantitatively with an extended Dawber-Scott model. The results are in agreement with the recent experiments.

  13. Surface roughness evolution of nanocomposite thin films

    NARCIS (Netherlands)

    Turkin, A; Pei, Y.T.; Shaha, K.P.; Chen, C.Q.; Vainchtein, David; Hosson, J.Th.M. De

    2009-01-01

    An analysis of dynamic roughening and smoothening mechanisms of thin films grown with pulsed-dc magnetron sputtering is presented. The roughness evolution has been described by a linear stochastic equation, which contains the second- and fourth-order gradient terms. Dynamic smoothening of the growin

  14. Monte Carlo simulation of magnetic nanostructured thin films

    Institute of Scientific and Technical Information of China (English)

    Guan Zhi-Qiang; Yutaka Abe; Jiang Dong-Hua; Lin Hai; Yoshitake Yamazakia; Wu Chen-Xu

    2004-01-01

    @@ Using Monte Carlo simulation, we have compared the magnetic properties between nanostructured thin films and two-dimensional crystalline solids. The dependence of nanostructured properties on the interaction between particles that constitute the nanostructured thin films is also studied. The result shows that the parameters in the interaction potential have an important effect on the properties of nanostructured thin films at the transition temperatures.

  15. Practical design and production of optical thin films

    CERN Document Server

    Willey, Ronald R

    2002-01-01

    Fundamentals of Thin Film Optics and the Use of Graphical Methods in Thin Film Design Estimating What Can Be Done Before Designing Fourier Viewpoint of Optical Coatings Typical Equipment for Optical Coating Production Materials and Process Know-How Process Development Monitoring and Control of Thin Film Growth Appendix: Metallic and Semiconductor Material Graphs Author IndexSubject Index

  16. Sintering and dielectric properties of fine-grained BaTiO3 ceramics

    Institute of Scientific and Technical Information of China (English)

    栾伟玲; 高濂; 郭景坤

    1999-01-01

    A new sintering method, spark plasma sintering (SPS), is described for the sintering of fine-grained BaTiO3 ceramics. Dense ceramics with fine grain size of near 170 nm are obtained using SPS at low temperature of 900℃ without holding time. The dielectric measurements of various grain size specimens show that the dielectric constants decrease with the reduce of grain size, and diffuse phase transition showed in the dielectric-temperature spectra. The variation in dielectric properties with grain size is explained.

  17. Linear electro-optical properties of tetragonal BaTiO3

    Indian Academy of Sciences (India)

    P U Sastry

    2002-09-01

    Linear optical susceptibility and clamped linear electro-optical tensor coefficients of tetragonal BaTiO3 are calculated using a formalism based on bond charge theory. Calculated values are in close agreement with experimental data. The covalent Ti–O bonds constituting distorted TiO6 octahedral groups are found to be major contributors to the electro-optic coefficients making them more sensitive than the BaO12 groups for these properties. Orientations of chemical bonds play an important role in determining these properties.

  18. Lattice sites of Cd in ferroelectric BaTiO$_3$

    CERN Document Server

    Dietrich, M; Deicher, M; Richter, F; Samokhvalov, V; Unterricker, S

    2002-01-01

    The radioactive isotope 111mCd was implanted into BaTiO3 in order to measure electric field gradients with Perturbed Angular Correlation spectroscopy (PAC). It is possible to anneal the implantation induced lattice damage to a certain extent. Then, 111mCd probes are positioned at two sites with distinct axially symmetric electric field gradients characterized by the quadrupole coupling constants of 33.9(9) and 69.8(9) MHz. These electric field gradients can be assigned to 111mCd at the Ti- and the Ba-sites.

  19. Thin Films Characterization by Ultra Trace Metrology

    International Nuclear Information System (INIS)

    Sensitive and accurate characterization of thin films used in nanoelectronics, thinner than a few nm, represents a challenge for many conventional methods, especially when considering in-line control. With capabilities in the E10 at/cm2 (2O3 tunnel oxide deposited on a magnetic stack. On the other hand, composition analysis by TXRF, and especially the detection of minor elements into thin films, requires the use of a specific incident angle to optimize sensitivity. Under the best conditions, determination of the composition of Co -based self aligned barriers (CoWP and CoWMoPB films with Co concentration >80%) is done with a precision of 6% on P, 8% on Mo and 13% on W (standard deviation)

  20. Hematite thin films: growth and characterization

    Science.gov (United States)

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Giratá, D.; Morales, A. L.; Devia, A.; Gómez, M. E.; Ramirez, J. G.; Gancedo, J. R.

    We have grown hematite (α - Fe 2 O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characteristic of bulk hematite phase in the weak ferromagnetic state. Also, the relative line intensity ratio suggests that the magnetization vector of the polycrystalline film is aligned preferentially parallel to the surface. The X-ray diffraction (XRD) pattern of the polycrystalline thin film grown on steel substrates also corresponds to α - Fe 2O3. The samples were also analyzed by Atomic Force Microscopy (AFM), those grown on stainless steel reveal a morphology consisting of columnar grains with random orientation, given the inhomogeneity of the substrate surface.

  1. Thin blend films of cellulose and polyacrylonitrile

    Science.gov (United States)

    Lu, Rui; Zhang, Xin; Mao, Yimin; Briber, Robert; Wang, Howard

    Cellulose is the most abundant renewable, biocompatible and biodegradable natural polymer. Cellulose exhibits excellent chemical and mechanical stability, which makes it useful for applications such as construction, filtration, bio-scaffolding and packaging. To further expand the potential applications of cellulose materials, their alloying with synthetic polymers has been investigated. In this study, thin films of cotton linter cellulose (CLC) and polyacrylonitrile (PAN) blends with various compositions spanning the entire range from neat CLC to neat PAN were spun cast on silicon wafers from common solutions in dimethyl sulfoxide / ionic liquid mixtures. The morphologies of thin films were characterized using optical microscopy, atomic force microscopy, scanning electron microscopy and X-ray reflectivity. Morphologies of as-cast films are highly sensitive to the film preparation conditions; they vary from featureless smooth films to self-organized ordered nano-patterns to hierarchical structures spanning over multiple length scales from nanometers to tens of microns. By selectively removing the PAN-rich phase, the structures of blend films were studied to gain insights in their very high stability in hot water, acid and salt solutions.

  2. Development of Bismuth-based Lead-free Piezoelectric Materials: Thin Film Piezoelectric Materials via PVD and CSD Routes

    Science.gov (United States)

    Jeon, Yu Hong

    Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems. Bismuth-based perovskite piezoelectric materials such as (Bi0.5,Na0.5)TiO3 - (Bi0.5K 0.5)TiO3 (BNT - BKT), (Bi0.5,Na0.5 )TiO3 - (Bi0.5K0.5)TiO3 - BaTiO3(BNT - BKT - BT), (Bi0.5K 0.5)TiO3 - Bi(Zn0.5,Ti0.5)O 3 (BKT - BZT), and (Bi0.5,Na0.5)TiO 3 - (Bi0.5K0.5)TiO3 - Bi(Mg 0.5,Ti0.5)O3 (BNT - BKT - BMgT) have been explored as potential alternatives to PZT. These materials systems have been extensively studied in bulk ceramic form, however many of the ultimate applications will be in thin film embodiments (i.e., microelectromechanical systems). For this reason, in this thesis these lead-free piezoelectrics are synthesized in thin film form to understand the structure-property-processing relationships and their impact on the ultimate device response. Fabrication of high quality of 0.95BKT - 0.05BZT thin films on platinized silicon substrates was attempted by pulsed laser deposition. Due to cation volatility, deposition parameters such as substrate temperature, deposition pressure, and target-substrate distance, as well as target overdoping were explored to achieve phase pure materials. This route led to high dielectric loss, indicative of poor ferroelectric behavior. This was likely a result of the poor thin film morphology observed in films deposited via this method. Subsequently, 0.8BNT - 0.2BKT, 85BNT - 10BKT - 5BT, and 72.5BNT - 22.5BKT - 5BMgT (near morphotropic phase boundary composition) were synthesized via chemical solution deposition. To compensate the loss of A-site cations, overdoped precursor solutions were prepared. Crystallization after each spin cast layer were required to

  3. Thin film bismuth iron oxides useful for piezoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  4. Polycrystalline thin film materials and devices

    Energy Technology Data Exchange (ETDEWEB)

    Baron, B.N.; Birkmire, R.W.; Phillips, J.E.; Shafarman, W.N.; Hegedus, S.S.; McCandless, B.E. (Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion)

    1992-10-01

    Results of Phase II of a research program on polycrystalline thin film heterojunction solar cells are presented. Relations between processing, materials properties and device performance were studied. The analysis of these solar cells explains how minority carrier recombination at the interface and at grain boundaries can be reduced by doping of windows and absorber layers, such as in high efficiency CdTe and CuInSe{sub 2} based solar cells. The additional geometric dimension introduced by the polycrystallinity must be taken into consideration. The solar cells are limited by the diode current, caused by recombination in the space charge region. J-V characteristics of CuInSe{sub 2}/(CdZn)S cells were analyzed. Current-voltage and spectral response measurements were also made on high efficiency CdTe/CdS thin film solar cells prepared by vacuum evaporation. Cu-In bilayers were reacted with Se and H{sub 2}Se gas to form CuInSe{sub 2} films; the reaction pathways and the precursor were studied. Several approaches to fabrication of these thin film solar cells in a superstrate configuration were explored. A self-consistent picture of the effects of processing on the evolution of CdTe cells was developed.

  5. Thin-film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1987-10-01

    Cadmium telluride, with a room-temperature band-gap energy of 1.5 eV, is a promising thin-film photovoltaic material. The major objective of this research has been to demonstrate thin-film CdTe heterojunction solar cells with a total area greater than 1 sq cm and photovoltaic efficiencies of 13 percent or more. Thin-film p-CdTe/CdS/SnO2:F/glass solar cells with an AM1.5 efficiency of 10.5 percent have been reported previously. This report contains results of work done on: (1) the deposition, resistivity control, and characterization of p-CdTe films by the close-spaced sublimation process; (2) the deposition of large-band-gap window materials; (3) the electrical properties of CdS/CdTe heterojunctions; (4) the formation of stable, reproducible, ohmic contacts (such as p-HgTe) to p-CdTe; and (5) the preparation and evaluation of heterojunction solar cells.

  6. When are thin films of metals metallic?

    Science.gov (United States)

    Plummer, E. W.; Dowben, P. A.

    1993-04-01

    There is an increasing body of experimental information suggesting that very thin films of materials, normally considered to be metals, exhibit behavior characteristic of a nonmetal. In almost all cases, there is a nonmetal-to-metal transition as a function of film density or thickness, frequently accompanied by a structural transition. Amazingly, this behavior seems to occur for metal films on metal substrates, as well as for metals on semiconductors. The identification of this phenomena and the subsequent explanation has been slow in developing, due to the inability to directly measure the conductivity of a submonolayer film. This paper will discuss the evidence accumulated from variety of spectroscopic experimental techniques for three systems: a Mott-Hubbard transition, a Peierls-like distortion, and a Wilson transition.

  7. Energetic deposition of thin metal films

    CERN Document Server

    Al-Busaidy, M S K

    2001-01-01

    deposited films. The primary aim of this thesis was to study the physical effect of energetic deposition metal thin films. The secondary aim is to enhance the quality of the films produced to a desired quality. Grazing incidence X-ray reflectivity (GIXR) measurements from a high-energy synchrotron radiation source were carried out to study and characterise the samples. Optical Profilers Interferometery, Atomic Force Microscope (AFM), Auger electron spectroscopy (AES), Medium energy ion spectroscopy (MEIS), and the Electron microscope studies were the other main structural characterisation tools used. AI/Fe trilayers, as well as multilayers were deposited using a Nordico planar D.C. magnetron deposition system at different voltage biases and pressures. The films were calibrated and investigated. The relation between energetic deposition variation and structural properties was intensely researched. Energetic deposition refers to the method in which the deposited species possess higher kinetic energy and impact ...

  8. Ferroelectric BaTiO3 phase of orthorhombic crystal structure contained in nanoparticles

    Science.gov (United States)

    Ram, S.; Jana, A.; Kundu, T. K.

    2007-09-01

    Ferroelectric BaTiO3 phase of a Pnma orthorhombic crystal structure is synthesized from a chemical method using a polymer complex of Ba2+ and Ti4+ with polyvinyl alcohol (PVA). After burning out the polymer at temperature as high as 550 °C in air for 2 h results in an average 15 nm crystallite BaTiO3 size, with lattice parameters a =0.6435 nm, b =0.5306 nm, c =0.8854 nm, and density 5.124 g/cm3. The relationship between dielectric constant ɛr and temperature showed a single Curie transition temperature TC=131 °C, with as large a ɛr value as 263 at TC. A low value of dissipation factor tan δ, as small as 0.033 at room temperature (frequency f =1 kHz), with good insulating properties made the sample promising for use in uncooled infrared detectors and thermal imaging applications. The ɛr value is nearly independent of f value up to 100 kHz. A spectrum of sharp EPR signals of g values 2.21 to 1.88 characterizes three major kinds of VBa-, VTi3-, and Ti3+-Vo2+ paramagnetic species present in the imperfections.

  9. Microwave dielectric characterisation of 3D-printed BaTiO3/ABS polymer composites.

    Science.gov (United States)

    Castles, F; Isakov, D; Lui, A; Lei, Q; Dancer, C E J; Wang, Y; Janurudin, J M; Speller, S C; Grovenor, C R M; Grant, P S

    2016-03-04

    3D printing is used extensively in product prototyping and continues to emerge as a viable option for the direct manufacture of final parts. It is known that dielectric materials with relatively high real permittivity-which are required in important technology sectors such as electronics and communications-may be 3D printed using a variety of techniques. Among these, the fused deposition of polymer composites is particularly straightforward but the range of dielectric permittivities available through commercial feedstock materials is limited. Here we report on the fabrication of a series of composites composed of various loadings of BaTiO3 microparticles in the polymer acrylonitrile butadiene styrene (ABS), which may be used with a commercial desktop 3D printer to produce printed parts containing user-defined regions with high permittivity. The microwave dielectric properties of printed parts with BaTiO3 loadings up to 70 wt% were characterised using a 15 GHz split post dielectric resonator and had real relative permittivities in the range 2.6-8.7 and loss tangents in the range 0.005-0.027. Permittivities were reproducible over the entire process, and matched those of bulk unprinted materials, to within ~1%, suggesting that the technique may be employed as a viable manufacturing process for dielectric composites.

  10. Microwave dielectric characterisation of 3D-printed BaTiO3/ABS polymer composites.

    Science.gov (United States)

    Castles, F; Isakov, D; Lui, A; Lei, Q; Dancer, C E J; Wang, Y; Janurudin, J M; Speller, S C; Grovenor, C R M; Grant, P S

    2016-01-01

    3D printing is used extensively in product prototyping and continues to emerge as a viable option for the direct manufacture of final parts. It is known that dielectric materials with relatively high real permittivity-which are required in important technology sectors such as electronics and communications-may be 3D printed using a variety of techniques. Among these, the fused deposition of polymer composites is particularly straightforward but the range of dielectric permittivities available through commercial feedstock materials is limited. Here we report on the fabrication of a series of composites composed of various loadings of BaTiO3 microparticles in the polymer acrylonitrile butadiene styrene (ABS), which may be used with a commercial desktop 3D printer to produce printed parts containing user-defined regions with high permittivity. The microwave dielectric properties of printed parts with BaTiO3 loadings up to 70 wt% were characterised using a 15 GHz split post dielectric resonator and had real relative permittivities in the range 2.6-8.7 and loss tangents in the range 0.005-0.027. Permittivities were reproducible over the entire process, and matched those of bulk unprinted materials, to within ~1%, suggesting that the technique may be employed as a viable manufacturing process for dielectric composites. PMID:26940381

  11. Microwave dielectric characterisation of 3D-printed BaTiO3/ABS polymer composites

    Science.gov (United States)

    Castles, F.; Isakov, D.; Lui, A.; Lei, Q.; Dancer, C. E. J.; Wang, Y.; Janurudin, J. M.; Speller, S. C.; Grovenor, C. R. M.; Grant, P. S.

    2016-03-01

    3D printing is used extensively in product prototyping and continues to emerge as a viable option for the direct manufacture of final parts. It is known that dielectric materials with relatively high real permittivity—which are required in important technology sectors such as electronics and communications—may be 3D printed using a variety of techniques. Among these, the fused deposition of polymer composites is particularly straightforward but the range of dielectric permittivities available through commercial feedstock materials is limited. Here we report on the fabrication of a series of composites composed of various loadings of BaTiO3 microparticles in the polymer acrylonitrile butadiene styrene (ABS), which may be used with a commercial desktop 3D printer to produce printed parts containing user-defined regions with high permittivity. The microwave dielectric properties of printed parts with BaTiO3 loadings up to 70 wt% were characterised using a 15 GHz split post dielectric resonator and had real relative permittivities in the range 2.6–8.7 and loss tangents in the range 0.005–0.027. Permittivities were reproducible over the entire process, and matched those of bulk unprinted materials, to within ~1%, suggesting that the technique may be employed as a viable manufacturing process for dielectric composites.

  12. Microwave dielectric characterisation of 3D-printed BaTiO3/ABS polymer composites

    Science.gov (United States)

    Castles, F.; Isakov, D.; Lui, A.; Lei, Q.; Dancer, C. E. J.; Wang, Y.; Janurudin, J. M.; Speller, S. C.; Grovenor, C. R. M.; Grant, P. S.

    2016-01-01

    3D printing is used extensively in product prototyping and continues to emerge as a viable option for the direct manufacture of final parts. It is known that dielectric materials with relatively high real permittivity—which are required in important technology sectors such as electronics and communications—may be 3D printed using a variety of techniques. Among these, the fused deposition of polymer composites is particularly straightforward but the range of dielectric permittivities available through commercial feedstock materials is limited. Here we report on the fabrication of a series of composites composed of various loadings of BaTiO3 microparticles in the polymer acrylonitrile butadiene styrene (ABS), which may be used with a commercial desktop 3D printer to produce printed parts containing user-defined regions with high permittivity. The microwave dielectric properties of printed parts with BaTiO3 loadings up to 70 wt% were characterised using a 15 GHz split post dielectric resonator and had real relative permittivities in the range 2.6–8.7 and loss tangents in the range 0.005–0.027. Permittivities were reproducible over the entire process, and matched those of bulk unprinted materials, to within ~1%, suggesting that the technique may be employed as a viable manufacturing process for dielectric composites. PMID:26940381

  13. Mesoscale flux-closure domain formation in single-crystal BaTiO3.

    Science.gov (United States)

    McQuaid, R G P; McGilly, L J; Sharma, P; Gruverman, A; Gregg, J M

    2011-01-01

    Over 60 years ago, Charles Kittel predicted that quadrant domains should spontaneously form in small ferromagnetic platelets. He expected that the direction of magnetization within each quadrant should lie parallel to the platelet surface, minimizing demagnetizing fields,and that magnetic moments should be configured into an overall closed loop, or flux-closure arrangement. Although now a ubiquitous observation in ferromagnets, obvious flux-closure patterns have been somewhat elusive in ferroelectric materials. This is despite the analogous behaviour between these two ferroic subgroups and the recent prediction of dipole closure states by atomistic simulations research. Here we show Piezoresponse Force Microscopy images of mesoscopic dipole closure patterns in free-standing, single-crystal lamellae of BaTiO(3). Formation of these patterns is a dynamical process resulting from system relaxation after the BaTiO(3) has been poled with a uniform electric field. The flux-closure states are composed of shape conserving 90° stripe domains which minimize disclination stresses. PMID:21792183

  14. The Dielectric Properties and Preparation Method of BaTiO3/PVDF 0-3 Composites

    Institute of Scientific and Technical Information of China (English)

    XIONG Chuan-xi; CHEN Juan; DONG Li-jie; NAN Ce-wen; ZHANG Xuan

    2002-01-01

    A series of 0 - 3 composites of the polyvinylidene fluoride (PVDF) and BaTiO3 was prepared.BaTiO3 was modified with titanate coupling agent. The dielectric properties and the interfacial interaction of composites by different preparation methods were examined and cormpared. The result shows that the relative dielectric constant ε of the composite prepared in solution has a maximum value at about 70% weight fraction of BaTiO3and the dielectric loss tanδ increases rapidly when the fraction exceeds 70%. For the composite prepared in melt,the relative dielectric constant ε almost reaches a maximum value at about 60% weight fraction of BaTiO3 and the dielectric loss is comparatively lower. The dielectric properties of composites are improved by using a coupling agent.

  15. First-principles study for vacancy-induced magnetism in nonmagnetic ferroelectric BaTiO3.

    Science.gov (United States)

    Cao, D; Cai, M Q; Zheng, Yue; Hu, W Y

    2009-12-14

    The possibilities of vacancy-induced magnetism in perovskite BaTiO(3) are investigated by first-principles calculations. Calculated results show that both titanium and oxygen vacancies could induce magnetism, but the barium vacancy did not induce magnetism. New and interesting magnetic properties of half-metallic magnetism are found in BaTiO(3) induced by the Ti-vacancy. Based on the density of states and the spin charge density distribution of BaTiO(3), we discuss the different origins of magnetism induced by the partial spin-polarized O 2p states around Ti vacancies and the partially filled d-states Ti around the oxygen vacancies. The discrepancy between the magnetic moments in the cubic phase and the tetragonal phase is due to anisotropic spin polarization induced by structure distortions. Our calculations would enable exploring magneto-electric coupling in nonmagnetic ferroelectric oxides.

  16. Emergence of Long-Range Order in BaTiO3 from Local Symmetry-Breaking Distortions

    Science.gov (United States)

    Senn, M. S.; Keen, D. A.; Lucas, T. C. A.; Hriljac, J. A.; Goodwin, A. L.

    2016-05-01

    By using a symmetry motivated basis to evaluate local distortions against pair distribution function data, we show without prior bias, that the off-center Ti displacements in the archetypal ferroelectric BaTiO3 are zone centered and rhombohedral-like across its known ferroelectric and paraelectric phases. We construct a simple Monte Carlo model that captures our main experimental findings and demonstrate how the rich crystallographic phase diagram of BaTiO3 emerges from correlations of local symmetry-breaking distortions alone. Our results strongly support the order-disorder picture for these phase transitions, but can also be reconciled with the soft-mode theory of BaTiO3 that is supported by some spectroscopic techniques.

  17. Effect of Annealing on Ferroelectric Properties of Nanometre BaTiO3 Ceramics Prepared by High Pressure Sintering Method

    Institute of Scientific and Technical Information of China (English)

    LI Peng-Fei; JIN Chang-Qing; XIAO Chang-Jiang; WANG Feng-Ping; WANG Xiao-Hui; LI Long-Tu

    2007-01-01

    @@ Dense nanocrystalline BaTiO3 ceramics with a grain size of 50nm are prepared under 6 GPa at 1273K using a high pressure sintering method. The sintered bulk is uniform and the relative density is above 97%. We anneal the ceramic samples in oxygen with various temperatures and for different times without apparent grain growth. After the annealing, several broadened peaks can be observed at about 378K by dielectric measurements. However,these peaks are very different from those of coarser-grained ceramics. It is indicated that both the elimination of oxygen vacancies and the release of residual stresses caused by high pressure greatly improve the overall ferroelectric properties of BaTiO3 ceramics. The observation of nearly linear polarization hysteresis loop after anneal provides the solid evidence of ferroelectricity in these nano-sized BaTiO3 ceramics.

  18. Thin Films for Coating Nanomaterials

    Institute of Scientific and Technical Information of China (English)

    S.M.Mukhopadhyay; P.Joshi; R.V.Pulikollu

    2005-01-01

    For nano-structured solids (those with one or more dimensions in the 1-100 nm range), attempts of surface modification can pose significant and new challenges. In traditional materials, the surface coating could be several hundreds nanometers in thickness, or even microns and millimeters. In a nano-structured material, such as particle or nanofibers, the coating thickness has to be substantially smaller than the bulk dimensions (100 nm or less), yet be durable and effective. In this paper, some aspects of effective nanometer scale coatings have been discussed. These films have been deposited by a non-line of sight (plasma)techniques; and therefore, they are capable of modifying nanofibers, near net shape cellular foams, and other high porosity materials. Two types of coatings will be focused upon: (a) those that make the surface inert and (b) those designed to enhance surface reactivity and bonding. The former has been achieved by forming 1-2 nm layer of -CF2- (and/or CF3) groups on the surface, and the latter by creating a nanolayer of SiO2-type compound. Nucleation and growth studies of the plasma-generated film indicate that they start forming as 2-3 nm high islands that grow laterally, and eventually completely cover the surface with 2-3nm film. Contact angle measurements indicate that these nano-coatings are fully functional even before they have achieved complete coverage of 2-3 nm. They should therefore be applicable to nano-structural solids.This is corroborated by application of these films on vapor grown nanofibers of carbon, and on graphitic foams. Coated and uncoated materials are infiltrated with epoxy matrix to form composites and their microstructure, as well as mechanical behaviors are compared. The results show that the nano-oxide coating can significantly enhance bond formation between carbon and organic phases, thereby enhancing wettability,dispersion, and composite behavior. The fluorocarbon coating, as expected, reduces bond formation, and

  19. Optical thin films and coatings from materials to applications

    CERN Document Server

    Flory, Francois

    2013-01-01

    Optical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. This book provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas.$bOptical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. Optical thin films and coatings provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas. Part one explores the design and manufacture of optical coatings. Part two highlights unconventional features of optical thin films including scattering properties of random structures in thin films, optical properties of thin film materials at short wavelengths, thermal properties and colour effects. Part three focusses on novel materials for optical thin films and coatings...

  20. Effects of Nd, Sm, Gd, Dy, Er Dopant on Electrical Properties of BaTiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Hao Sue; Wei Yongde; Xing Xiaoxu

    2004-01-01

    BaTiO3 ceramics doped with various quantities of Nd2O3, Sm2O3, Gd2O3, Dy2O3 and Er2O3 were prepared respectively ( the adulterate concentrations were 0. 001,0. 002, 0. 003, 0.005, 0. 007 mol fraction) through a sol-gel method and their electrical properties were researched. It is found that each adulteration of Nd2O3, Sm2O3 Gd2O3,Dy2O3 and Er2O3 all can make the resistivity of BaTiO3 ceramics decline , especially Sm2O3 and Gd2O3. When the addition of Sm2O3 is 0. 001 mol, the resistivity is the smallest, declining from 4.0 × 1012 to 6.5 × 103 Ω different kind of rare earth exhibits different regularity. The grain resistance of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 exhibits a NTC effect, at the same time the grain boundary resistance has a PTC effect, and the grain boundary resistance is much larger than the grain resistance, so the PTC effects of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 originate from the grain boundary. The additions of Nd2O3 , Gd2O3 or Er2O3 make the dielectric constant and the dielectric loss of BaTiO3 ceramics change evidently, especially Nd2O3. The dielectric constant is larger than that of pure BaTiO3 ceramics, on the other hand, the dielectric loss is much lower, which is useful in capacitor fields.

  1. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  2. INVESTIGATION OF PHOTOELECTROCHROMIC THIN FILM AND DEVICE

    Institute of Scientific and Technical Information of China (English)

    M.J. Chen; H. Shen

    2005-01-01

    Photoelectrochromic device is a combination of dye-sensitized solar cells and electrochromic WO3 layers. Ectrochroelmic WO3 layer and TiO2 layer had been prepared by the sol-gel process, then be assembled to pohotoelectrochromic device. The effects of heating temperature on photoelectrochromic were investigated. The results showed that thin films prepared by dip-coating and spin-coating had good film quality and the device made by the method mentioned in the paper had good photoelectrochromie properties.

  3. Thermoviscoelastic models for polyethylene thin films

    DEFF Research Database (Denmark)

    Li, Jun; Kwok, Kawai; Pellegrino, Sergio

    2016-01-01

    This paper presents a constitutive thermoviscoelastic model for thin films of linear low-density polyethylene subject to strains up to yielding. The model is based on the free volume theory of nonlinear thermoviscoelasticity, extended to orthotropic membranes. An ingredient of the present approach...... is that the experimentally inaccessible out-of-plane material properties are determined by fitting the model predictions to the measured nonlinear behavior of the film. Creep tests, uniaxial tension tests, and biaxial bubble tests are used to determine the material parameters. The model has been validated experimentally...

  4. Thin film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, Shirley S.; Ang, S. T.; Mantravadi, M. K.

    1987-08-01

    Thin-film p-CdTe/CdS/SnO2:F/glass solar cells of the inverted configuration were prepared by the deposition of p-type CdTe films onto CdS/SnO2:F/glass substrates using CVD or close-spaced sublimation (CSS) techniques based on the procedures of Chu et al. (1983) and Nicholl (1963), respectively. The deposition rates of p-CdTe films deposited by CSS were higher than those deposited by the CVD technique (4-5 min were sufficient), and the efficiencies higher than 10 percent were obtained. However, the resistivity of films prepared by CSS was not as readily controlled as that of the CVD films. The simplest technique to reduce the resistivity of the CSS p-CdTe films was to incorporate a dopant, such as As or Sb, into the reaction mixture during the preparation of the source material. The films with resistivities in the range of 500-1000 ohm cm were deposited in this manner.

  5. Nitrogen doped zinc oxide thin film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sonny X.

    2003-12-15

    To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good quality, stable p-type ZnO material, ZnO remains an attractive material with potential for high performance short wavelength optoelectronic devices. One may argue that gallium nitride was in a similar situation a decade ago. Although we did not obtain any p-type conductivity, we hope our research will provide a valuable reference to the literature.

  6. Polycrystalline thin films FY 1992 project report

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K. [ed.

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting ``next-generation`` options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called ``government/industry partnerships``) that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  7. Polycrystalline thin films FY 1992 project report

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K. (ed.)

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting next-generation'' options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called government/industry partnerships'') that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  8. Multiferroic oxide thin films and heterostructures

    KAUST Repository

    Lu, Chengliang

    2015-05-26

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  9. Multiferroic oxide thin films and heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chengliang, E-mail: cllu@mail.hust.edu.cn, E-mail: Tao.Wu@kaust.edu.sa [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Hu, Weijin; Wu, Tom, E-mail: cllu@mail.hust.edu.cn, E-mail: Tao.Wu@kaust.edu.sa [Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Tian, Yufeng [School of Physics, Shandong University, Jinan 250100 (China)

    2015-06-15

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  10. EBSD analysis of electroplated magnetite thin films

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Teng, C. L.; Ryan, M. P.; Hartmann, U.; Mücklich, F.

    2010-05-01

    By means of electron backscatter diffraction (EBSD), we analyse the crystallographic orientation of electroplated magnetite thin films on Si/copper substrates. Varying the voltage during the electroplating procedure, the resulting surface properties are differing considerably. While a high voltage produces larger but individual grains on the surface, the surfaces become smoother on decreasing voltage. Good quality Kikuchi patterns could be obtained from all samples; even on individual grains, where the surface and the edges could be measured. The spatial resolution of the EBSD measurement could be increased to about 10 nm; thus enabling a detailed analysis of single magnetite grains. The thin film samples are polycrystalline and do not exhibit a preferred orientation. EBSD reveals that the grain size changes depending on the processing conditions, while the detected misorientation angles stay similar.

  11. Generalized Ellipsometry on Ferromagnetic Sculptured Thin Films.

    Science.gov (United States)

    Schmidt, Daniel; Hofmann, Tino; Mok, Kah; Schmidt, Heidemarie; Skomski, Ralf; Schubert, Eva; Schubert, Mathias

    2011-03-01

    We present and discuss generalized ellipsometry and generalized vector-magneto-optic ellipsometry investigations on cobalt nanostructured thin films with slanted, highly-spatially coherent, columnar arrangement. The samples were prepared by glancing angle deposition. The thin films are highly transparent and reveal strong form-induced birefringence. We observe giant Kerr rotation in the visible spectral region, tunable by choice of the nanostructure geometry. Spatial magnetization orientation hysteresis and magnetization magnitude hysteresis properties are studied using a 3-dimensional Helmholtz coil arrangement allowing for arbitrary magnetic field direction at the sample position for field strengths up to 0.4 Tesla. Analysis of data obtained within this novel vector-magneto-optic setup reveals magnetization anisotropy of the Co slanted nanocolumns supported by mean-field theory modeling.

  12. Thin film sensors for measuring small forces

    OpenAIRE

    F. Schmaljohann; Hagedorn, D.; LÖffler, F.

    2015-01-01

    Especially in the case of measuring small forces, the use of conventional foil strain gauges is limited. The measurement uncertainty rises by force shunts and is due to the polymer foils used, as they are susceptible to moisture. Strain gauges in thin film technology present a potential solution to overcome these effects because of their direct and atomic contact with the measuring body, omitting an adhesive layer and the polymer foil. For force measurements up to 1 N, a...

  13. Surface morphology of thin films polyoxadiazoles

    OpenAIRE

    J. Weszka; M.M. Szindler; M. Chwastek-Ogierman; M. Bruma; P. Jarka; Tomiczek, B.

    2011-01-01

    urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used....

  14. Recent developments in thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dhere, N.G. (Inst. Militar de Engenharia, Rio de Janeiro, RJ (Brazil))

    1990-12-15

    In recent years, remarkable progress has been made in improving the photovoltaic (PV) conversion efficiencies of thin film solar cells. The best active-area efficiencies (air mass 1.5) of thin film solar cells reported are as follows: polycrystalline CuInSe{sub 2}, 14.1%; CuIn(Ga)Se{sub 2}, 12.9%; CdTe, 12.3%, total area; single-junction hydrogenated amorphous silicon (a-Si:H), 12.0%; multiple-junction a-Si:H, 13.3%; cleaved epitaxial GaAs-Ga{sub 1-x}Al{sub x}As, 21.5%, total area. Laboratory methods for preparing small thin film solar cells are evaporation, closed-space sublimation, closed-space vapor transport, vapor phase epitaxy and metallo-organic chemical vapor deposition, while economic large-area deposition techniques such as sputtering, glow discharge reduction, electrodeposition, spraying and screen printing are being used for module fabrication. The following aperture-area efficiencies have been measured, at the Solar Energy Research Inst., for thin film modules: a-Si:H, 9.8%, 933 cm{sup 2}; CuIn(Ga)Se{sub 2}, 11.1%, 938 cm{sup 2}; CdTe, 7.3%, 838 cm{sup 2}. The instability issue of a-Si:H continues to be a high priority area. It is necessary to improve the open-circuit voltage of CuIn(Ga)Se{sub 2} cells, which do not seem to exhibit any intrinsic degradation mechanisms. With continued progress and increased production, PV modules are likely to become competitive for medium-scale power requirements in the mid-1990s. (orig.).

  15. Amorphous silicon for thin-film transistors

    OpenAIRE

    Schropp, Rudolf Emmanuel Isidore

    1987-01-01

    Hydrogenated amorphous silicon (a-Si:H) has considerable potential as a semiconducting material for large-area photoelectric and photovoltaic applications. Moreover, a-Si:H thin-film transistors (TFT’s) are very well suited as switching devices in addressable liquid crystal display panels and addressable image sensor arrays, due to a new technology of low-cost, Iow-temperature processing overlarge areas. ... Zie: Abstract

  16. Quantized Nanocrystalline CdTe Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline CdTe thin films were prepared by asymmetric rectangular pulse electrodeposition in organic solution at 110°C. STM image shows a porous network morphology constructed by interconnected spherical CdTe crystallites with a mean diameter of 4.2 nm. A pronounced size quantization was indicated in the action and absorption spectra. Potentials dependence dual conductive behavior was revealed in the photocurrent-potential (I-V) curves.

  17. Ferromagnetic Liquid Thin Films Under Applied Field

    OpenAIRE

    Banerjee, S.; Widom, M.

    1999-01-01

    Theoretical calculations, computer simulations and experiments indicate the possible existence of a ferromagnetic liquid state, although definitive experimental evidence is lacking. Should such a state exist, demagnetization effects would force a nontrivial magnetization texture. Since liquid droplets are deformable, the droplet shape is coupled with the magnetization texture. In a thin-film geometry in zero applied field, the droplet has a circular shape and a rotating magnetization texture ...

  18. Electrochemical Analysis of Conducting Polymer Thin Films

    OpenAIRE

    Bin Wang; Vyas, Ritesh N.

    2010-01-01

    Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting...

  19. Structures for dense, crack free thin films

    Science.gov (United States)

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2011-03-08

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  20. Electrical characterization of thin film ferroelectric capacitors

    OpenAIRE

    Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D; Keur, W.; J. Schmitz; Hueting, R.J.E.

    2006-01-01

    Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offer a re-use of electronic circuitry, low tuning voltages, a high capacitance density, a low cost, a presence of bulk acoustic wave resonance(s) and decoupling functionality. The basic operation and ...

  1. Thin-film silicon solar cell technology

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.V.; Meier, J.; Kroll, U.; Droz, C.; Bailat, J. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Schade, H. [RWE Schott Solar GmbH, Putzbrunn (Germany); Vanecek, M. [Academy of Sciences, Prague (Czech Republic). Inst. of Physics; Vallat Sauvain, E.; Wyrsch, N. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Unaxis SPTec S A, Neuchatel (Switzerland)

    2004-07-01

    This paper describes the use, within p-i-n- and n-i-p-type solar cells, of hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon ({mu}c-Si:H) thin films (layers), both deposited at low temperatures (200{sup o}C) by plasma-assisted chemical vapour deposition (PECVD), from a mixture of silane and hydrogen. Optical and electrical properties of the i-layers are described. These properties are linked to the microstructure and hence to the i-layer deposition rate, that in turn, affects throughput in production. The importance of contact and reflection layers in achieving low electrical and optical losses is explained, particularly for the superstrate case. Especially the required properties for the transparent conductive oxide (TCO) need to be well balanced in order to provide, at the same time, for high electrical conductivity (preferably by high electron mobility), low optical absorption and surface texture (for low optical losses and pronounced light trapping). Single-junction amorphous and microcrystalline p-i-n-type solar cells, as fabricated so far, are compared in their key parameters (J{sub sc},FF,V{sub oc}) with the [theoretical] limiting values. Tandem and multijunction cells are introduced; the {mu}c-Si: H/a-Si: H or [micromorph] tandem solar cell concept is explained in detail, and recent results obtained here are listed and commented. Factors governing the mass-production of thin-film silicon modules are determined both by inherent technical reasons, described in detail, and by economic considerations. The cumulative effect of these factors results in distinct efficiency reductions from values of record laboratory cells to statistical averages of production modules. Finally, applications of thin-film silicon PV modules, especially in building-integrated PV (BIPV) are shown. In this context, the energy yields of thin-film silicon modules emerge as a valuable gauge for module performance, and compare very favourably with those of

  2. Fluxoid dynamics in superconducting thin film rings

    OpenAIRE

    Kirtley, J. R.; Tsuei, C. C.; Kogan, V. G.; Clem, J. R.; Raffy, H.; Li, Z. Z.

    2003-01-01

    We have measured the dynamics of individual magnetic fluxoids entering and leaving photolithographically patterned thin film rings of the underdoped high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\\delta}$, using a variable sample temperature scanning SQUID microscope. These results can be qualitatively described using a model in which the fluxoid number changes by thermally activated nucleation of a Pearl vortex in, and transport of the Pearl vortex across, the ring wall.

  3. Ferroelectric properties of barium strontium titanate thin films grown by RF co-sputtering

    International Nuclear Information System (INIS)

    In this work, we present the variation of the ferroelectric properties of Ba1-xSrxTiO3 films deposited on Pt/TiO2/SiO2/Si substrates by RF co-sputtering with 0≤x≤1. The co-sputtering was done using a single magnetron with BaTiO3/SrTiO3 targets in a pie mosaics configuration. Smooth and uniform films were obtained using the same conditions of growth and annealing temperature. The X-ray diffraction and EDS results show that the processes were managed to obtain crystalline materials with x from 0 to 1. The behaviour of P-E loops suggests that the ferroelectric properties of the films were tuned by changing the concentration of the cation. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Superconducting properties of iron chalcogenide thin films

    Directory of Open Access Journals (Sweden)

    Paolo Mele

    2012-01-01

    Full Text Available Iron chalcogenides, binary FeSe, FeTe and ternary FeTexSe1−x, FeTexS1−x and FeTe:Ox, are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i easy fabrication and epitaxial growth on common single-crystal substrates; (ii strong enhancement of superconducting transition temperature with respect to the bulk parent compounds (in FeTe0.5Se0.5, zero-resistance transition temperature Tc0bulk = 13.5 K, but Tc0film = 19 K on LaAlO3 substrate; (iii high critical current density (Jc ~ 0.5 ×106 A cm2 at 4.2 K and 0 T for FeTe0.5Se0.5 film deposited on CaF2, and similar values on flexible metallic substrates (Hastelloy tapes buffered by ion-beam assisted deposition with a weak dependence on magnetic field; (iv high upper critical field (~50 T for FeTe0.5Se0.5, Bc2(0, with a low anisotropy, γ ~ 2. These highlights explain why thin films of iron chalcogenides have been widely studied in recent years and are considered as promising materials for applications requiring high magnetic fields (20–50 T and low temperatures (2–10 K.

  5. Thin film cadmium telluride photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.; Bohn, R. (Toledo Univ., OH (United States))

    1992-04-01

    This report describes research to develop to vacuum-based growth techniques for CdTe thin-film solar cells: (1) laser-driven physical vapor deposition (LDPVD) and (2) radio-frequency (rf) sputtering. The LDPVD process was successfully used to deposit thin films of CdS, CdTe, and CdCl{sub 2}, as well as related alloys and doped semiconductor materials. The laser-driven deposition process readily permits the use of several target materials in the same vacuum chamber and, thus, complete solar cell structures were fabricated on SnO{sub 2}-coated glass using LDPVD. The rf sputtering process for film growth became operational, and progress was made in implementing it. Time was also devoted to enhancing or implementing a variety of film characterization systems and device testing facilities. A new system for transient spectroscopy on the ablation plume provided important new information on the physical mechanisms of LDPVD. The measurements show that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a fraction that is highly excited internally ({ge} 6 eV), and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. 19 refs.

  6. Supramolecular structure of electroactive polymer thin films

    Science.gov (United States)

    Kornilov, V. M.; Lachinov, A. N.; Karamov, D. D.; Nabiullin, I. R.; Kul'velis, Yu. V.

    2016-05-01

    This paper presents the results of an experimental investigation of the supramolecular structure of polydiphenylenephthalide thin films that exhibit effects of resistive switching. The supramolecular structure of the polymer has been investigated using small-angle neutron scattering in conjunction with atomic force microscopy. It has been found that the internal structure of polymer films consists of structural elements in the form of spheroids. The sizes of the structural elements, which were obtained from the neutron scattering data and analysis of the atomic force microscopy images, correlate well with each other. A model of the formation of polymer layers has been proposed. The observed structural elements in polymer films are formed due to the association of macromolecules in the initial polymer solution.

  7. Electrical resistivity of thin metal films

    CERN Document Server

    Wissmann, Peter

    2007-01-01

    The aim of the book is to give an actual survey on the resistivity of thin metal and semiconductor films interacting with gases. We discuss the influence of the substrate material and the annealing treatment of the films, presenting our experimental data as well as theoretical models to calculate the scattering cross section of the conduction electrons in the frame-work of the scattering hypothesis. Main emphasis is laid on the comparison of gold and silver films which exhibit nearly the same lattice structure but differ in their chemical activity. In conclusion, the most important quantity for the interpretation is the surface charging z while the correlation with the optical data or the frustrated IR vibrations seems the show a more material-specific character. Z can be calculated on the basis of the density functional formalism or the self-consistent field approximation using Mulliken’s population analysis.

  8. Irradiation effects in YBCO thin films

    International Nuclear Information System (INIS)

    Oxide superconductors are very sensitive to electron or ion beam irradiation/implantation. In the past 19 years after high-Tc (HTc) superconductivity was discovered in these materials, many aspects of interactions of accelerated particles with HTc thin films were investigated. In this paper short review of most significant phenomena is given, especially of those important for electronic applications (controllable reduction of critical temperature and critical current density) and their applications for HTc film patterning, fabrication of HTc Josephson junctions and SQUIDs. Some new results in creating 3-d inhomogeneous regions in YBCO superconductors by ion irradiation/implantation and investigation of high harmonic generation in YBCO film modified by 100 keV oxygen ions are presented. (author)

  9. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  10. Magnetization relaxation in sputtered thin permalloy films

    Science.gov (United States)

    Oliveira, R. C.; Rodríguez-Suárez, R. L.; Aguiar, F. M. De; Rezende, S. M.; Fermin, J. R.; Azevedo, A.

    2004-05-01

    In order to understand the underlying phenomena of magnetization damping in metallic thin films, samples of permalloy films were grown by magnetron sputtering, and their 8.6-GHz ferromagnetic resonance linewidth ΔH has been measured as a function of the Permalloy (Py) film thickness t, at room temperature. We made samples of Py(t)/Si(001) and X/Py(t)/X/Si(001), with X=Pd (40Å), and Cr (25Å), with 20Å < t < 200Å. While ΔH scales with t-2 in the bare Py/Si series, it is shown that the damping behavior strongly depends on X in the sandwich samples.

  11. Nanocrystalline silicon based thin film solar cells

    Science.gov (United States)

    Ray, Swati

    2012-06-01

    Amorphous silicon solar cells and panels on glass and flexible substrate are commercially available. Since last few years nanocrystalline silicon thin film has attracted remarkable attention due to its stability under light and ability to absorb longer wavelength portion of solar spectrum. For amorphous silicon/ nanocrystalline silicon double junction solar cell 14.7% efficiency has been achieved in small area and 13.5% for large area modules internationally. The device quality nanocrystalline silicon films have been fabricated by RF and VHF PECVD methods at IACS. Detailed characterizations of the materials have been done. Nanocrystalline films with low defect density and high stability have been developed and used as absorber layer of solar cells.

  12. Preparation and properties of antimony thin film anode materials

    Institute of Scientific and Technical Information of China (English)

    SU Shufa; CAO Gaoshao; ZHAO Xinbing

    2004-01-01

    Metallic antimony thin films were deposited by magnetron sputtering and electrodeposition. Electrochemical properties of the thin film as anode materials for lithium-ion batteries were investigated and compared with those of antimony powder. It was found that both magnetron sputtering and electrodeposition are easily controllable processes to deposit antimony films with fiat charge/discharge potential plateaus. The electrochemical performances of antimony thin films, especially those prepared with magnetron sputtering, are better than those of antimony powder. The reversible capacities of the magnetron sputtered antimony thin film are above 400 mA h g-1 in the first 15 cycles.

  13. Magnetic and nonlinear optical properties of BaTiO3 nanoparticles

    Directory of Open Access Journals (Sweden)

    S. Ramakanth

    2015-05-01

    Full Text Available In our earlier studies the BaTiO3 samples were processed at higher temperatures like 1000oC and explained the observed magnetism in it. It is found that the charge transfer effects are playing crucial role in explaining the observed ferromagnetism in it. In the present work the samples were processed at lower temperatures like 650oC-800oC. The carrier densities in these particles were estimated to be ∼ 1019-1020/cm3 range. The band gap is in the range of 2.53eV to 3.2eV. It is observed that magnetization increased with band gap narrowing. The higher band gap narrowed particles exhibited increased magnetization with a higher carrier density of 1.23×1020/cm3 near to the Mott critical density. This hint the exchange interactions between the carriers play a dominant role in deciding the magnetic properties of these particles. The increase in charge carrier density in this undoped BaTiO3 is because of oxygen defects only. The oxygen vacancy will introduce electrons in the system and hence more charge carriers means more oxygen defects in the system and increases the exchange interactions between Ti3+, Ti4+, hence high magnetic moment. The coercivity is increased from 23 nm to 31 nm and then decreased again for higher particle size of 54 nm. These particles do not show photoluminescence property and hence it hints the absence of uniformly distributed distorted [TiO5]-[TiO6] clusters formation and charge transfer between them. Whereas these charge transfer effects are vital in explaining the observed magnetism in high temperature processed samples. Thus the variation of magnetic properties like magnetization, coercivity with band gap narrowing, particle size and charge carrier density reveals the super paramagnetic nature of BaTiO3 nanoparticles. The nonlinear optical coefficients extracted from Z-scan studies suggest that these are potential candidates for optical imaging and signal processing applications.

  14. Preparation and Characterization of BaTiO3-PbZrTiO3 Coating for Pyroelectric Energy Harvesting

    Science.gov (United States)

    Raghavendra, R. M.; Praneeth, K. P. S. S.; Dutta, Soma

    2016-08-01

    Harvesting energy from waste heat is a promising field of research as there are significant energy recovery opportunities from various waste thermal energy sources. The present study reports pyroelectric energy harvesting using thick film prepared from a (x)BaTiO3-(1 - x)PbZr0.52Ti0.48O3 (BT-PZT) solid solution. The developed BT-PZT system is engineered to tune the ferro to paraelectric phase transition temperature of it in-between the phase transition temperature of BaTiO3 (393 K) and PbZrTiO3 (573 K) with higher pyroelectric figure-of-merit (FOM). The temperature-dependent dielectric behavior of the material has revealed the ferro- to paraelectric phase transition at 427 K with a maximum dielectric constant of 755. The room-temperature (298 K) pyroelectric coefficient (Pi) of the material was obtained as 738.63 μC/m2K which has yielded a significantly high FOM of 1745.8 J m-3 K-2. The enhancement in pyroelectric property is attributed to the morphotopic phase transition between tetragonal and rhombohedral PZT phases in the BT-PZT system. The developed BT-PZT system is capable of generating a power output of 1.3 mW/m2 near the Curie temperature with a constant rate (0.11 K/s) of heating. A signal conditioning circuit has been developed to rectify the time-varying current and voltage signals obtained from the harvester during heating cycles. The output voltage generated by the pyroelectric harvester has been stored in a capacitor for powering wearable electronics.

  15. Preface: Thin films of molecular organic materials

    Science.gov (United States)

    Fraxedas, J.

    2008-03-01

    This special issue is devoted to thin films of molecular organic materials and its aim is to assemble numerous different aspects of this topic in order to reach a wide scientific audience. Under the term 'thin films', structures with thicknesses spanning from one monolayer or less up to several micrometers are included. In order to narrow down this relaxed definition (how thin is thin?) I suggest joining the stream that makes a distinction according to the length scale involved, separating nanometer-thick films from micrometer-thick films. While the physical properties of micrometer-thick films tend to mimic those of bulk materials, in the low nanometer regime new structures (e.g., crystallographic and substrate-induced phases) and properties are found. However, one has to bear in mind that some properties of micrometer-thick films are really confined to the film/substrate interface (e.g. charge injection), and are thus of nanometer nature. Supported in this dimensionality framework, this issue covers the most ideal and model 0D case, a single molecule on a surface, through to the more application-oriented 3D case, placing special emphasis on the fascinating 2D domain that is monolayer assembly. Thus, many aspects will be reviewed, such as single molecules, self-organization, monolayer regime, chirality, growth, physical properties and applications. This issue has been intentionally restricted to small molecules, thus leaving out polymers and biomolecules, because for small molecules it is easier to establish structure--property relationships. Traditionally, the preparation of thin films of molecular organic materials has been considered as a secondary, lower-ranked part of the more general field of this class of materials. The coating of diverse surfaces such as silicon, inorganic and organic single crystals, chemically modified substrates, polymers, etc., with interesting molecules was driven by the potential applications of such molecular materials

  16. Microwave dielectric properties of BNT-BT0.08 thin films prepared by sol-gel technique

    Science.gov (United States)

    Huitema, L.; Cernea, M.; Crunteanu, A.; Trupina, L.; Nedelcu, L.; Banciu, M. G.; Ghalem, A.; Rammal, M.; Madrangeas, V.; Passerieux, D.; Dutheil, P.; Dumas-Bouchiat, F.; Marchet, P.; Champeaux, C.

    2016-04-01

    We report for the first time the microwave characterization of 0.92(Bi0.5Na0.5)TiO3-0.08BaTiO3 (BNT-BT0.08) ferroelectric thin films fabricated by the sol-gel method and integrated in both planar and out-of-plane tunable capacitors for agile high-frequency applications and particularly on the WiFi frequency band from 2.4 GHz to 2.49 GHz. The permittivity and loss tangent of the realized BNT-BT0.08 layers have been first measured by a resonant cavity method working at 12.5 GHz. Then, we integrated the ferroelectric material in planar inter-digitated capacitors (IDC) and in out-of-plane metal-insulator-metal (MIM) devices and investigated their specific properties (dielectric tunability and losses) on the whole 100 MHz-15 GHz frequency domain. The 3D finite-elements electromagnetic simulations of the IDC capacitances are fitting very well with their measured responses and confirm the dielectric properties determined with the cavity method. While IDCs are not exhibiting an optimal tunability, the MIM capacitor devices with optimized Ir/MgO(100) bottom electrodes demonstrate a high dielectric tunability, of 30% at 2.45 GHz under applied voltages as low as 10 V, and it is reaching 50% under 20 V voltage bias at the same frequency. These high-frequency properties of the MIM devices integrating the BNT-BT0.08 films, combining a high tunability under low applied voltages indicate a wide integration potential for tunable devices in the microwave domain and particularly at 2.45 GHz, corresponding to the widely used industrial, scientific, and medical frequency band.

  17. Scanning tunneling spectroscopy of Pb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Michael

    2010-12-13

    The present thesis deals with the electronic structure, work function and single-atom contact conductance of Pb thin films, investigated with a low-temperature scanning tunneling microscope. The electronic structure of Pb(111) thin films on Ag(111) surfaces is investigated using scanning tunneling spectroscopy (STS). Quantum size effects, in particular, quantum well states (QWSs), play a crucial role in the electronic and physical properties of these films. Quantitative analysis of the spectra yields the QWS energies as a function of film thickness, the Pb bulk-band dispersion in {gamma}-L direction, scattering phase shifts at the Pb/Ag interface and vacuum barrier as well as the lifetime broadening at anti {gamma}. The work function {phi} is an important property of surfaces, which influences catalytic reactivity and charge injection at interfaces. It controls the availability of charge carriers in front of a surface. Modifying {phi} has been achieved by deposition of metals and molecules. For investigating {phi} at the atomic scale, scanning tunneling microscopy (STM) has become a widely used technique. STM measures an apparent barrier height {phi}{sub a}, which is commonly related to the sample work function {phi}{sub s} by: {phi}{sub a}=({phi}{sub s}+{phi}{sub t}- vertical stroke eV vertical stroke)/2, with {phi}{sub t} the work function of the tunneling tip, V the applied tunneling bias voltage, and -e the electron charge. Hence, the effect of the finite voltage in STM on {phi}{sub a} is assumed to be linear and the comparison of {phi}{sub a} measured at different surface sites is assumed to yield quantitative information about work function differences. Here, the dependence of {phi}{sub a} on the Pb film thickness and applied bias voltage V is investigated. {phi}{sub a} is found to vary significantly with V. This bias dependence leads to drastic changes and even inversion of contrast in spatial maps of {phi}{sub a}, which are related to the QWSs in the Pb

  18. Phase conjugator with two coherent beams in a BaTiO3: Ce crystal

    Institute of Scientific and Technical Information of China (English)

    武建劳; 谢平; 戴建华; 张洪钧

    2000-01-01

    A phase conjugator which includes two coherent beams that are incident upon one of a-faces of a BaTiO3: Ce crystal without internal reflection is performed experimentally. Based on the four-wave mixing, the mechanism of this conjugator is investigated numerically. in comparison with the cor-responding self-pumped phase conjugator, the phase-conjugate behavior of this conjugator is estab-lished much more quickly, its phase conjugate reflectivity is greater in some cases and the intensity threshold is lower by over two orders of magnitude. The configuration of this conjugator is easy to per-form because the output response exists over a wide range of angular and lateral positions of the two incident beams on the crystal.

  19. Negative Capacitance in BaTiO3/BiFeO3 Bilayer Capacitors.

    Science.gov (United States)

    Hou, Ya-Fei; Li, Wei-Li; Zhang, Tian-Dong; Yu, Yang; Han, Ren-Lu; Fei, Wei-Dong

    2016-08-31

    Negative capacitances provide an approach to reduce heat generations in field-effect transistors during the switch processes, which contributes to further miniaturization of the conventional integrated circuits. Although there are many studies about negative capacitances using ferroelectric materials, the direct observation of stable ferroelectric negative capacitances has rarely been reported. Here, we put forward a dc bias assistant model in bilayer capacitors, where one ferroelectric layer with large dielectric constant and the other ferroelectric layer with small dielectric constant are needed. Negative capacitances can be obtained when external dc bias electric fields are larger than a critical value. Based on the model, BaTiO3/BiFeO3 bilayer capacitors are chosen as study objects, and negative capacitances are observed directly. Additionally, the upward self-polarization effect in the ferroelectric layer reduces the critical electric field, which may provide a method for realizing zero and/or small dc bias assistant negative capacitances. PMID:27502999

  20. Influence of defects on ferroelectric and electrocaloric properties of BaTiO3

    Science.gov (United States)

    Grünebohm, Anna; Nishimatsu, Takeshi

    2016-04-01

    We report modifications of the ferroelectric and electrocaloric properties of BaTiO3 by defects. For this purpose, we have combined ab initio based molecular dynamics simulations with a simple model for defects. We find that different kinds of defects modify the ferroelectric transition temperatures and polarization, reduce the thermal hysteresis of the transition, and are no obstacle for a large caloric response. For a locally reduced polarization, the ferroelectric transition temperature and the adiabatic response are slightly reduced. For polar defects, an intriguing picture emerges. The transition temperature is increased by polar defects and the temperature range of the large caloric response is broadened. Even more remarkable, we find an inverse caloric effect in a broad temperature range.

  1. Response of the electric field gradient in ion implanted BaTiO$_{3}$ to an external electric field

    CERN Document Server

    Dietrich, M; Deicher, M; Freitag, K; Samokhvalov, V; Unterricker, S

    2001-01-01

    Single crystalline, ferroelectric BaTiO$_{3}$ as material with the highest piezoelectric constants among the perovskites with ordered sublattices was implanted with $^{111}$In($^{111}$Cd). The electric field gradient at the Ti position was measured with perturbed $\\gamma-\\gamma$-angular correlation spectroscopy (PAC) while the crystal was exposed to an external electric field. A quadratic dependence could be observed: $\

  2. The thermal conductivity of BaTiO3 in the neighbourhood of its ferroelectric transition temperatures

    NARCIS (Netherlands)

    Mante, A.J.H.; Volger, J.

    1967-01-01

    The thermal conductivity of single crystalline BaTiO3 has been measured in the temperature range of 100–500°K. In the neighbourhood of the transition temperature a reduction of the thermal conductivity is observed. This result can be explained in view of a current theory on ferroelectricity which in

  3. Cerium Dioxide Thin Films Using Spin Coating

    Directory of Open Access Journals (Sweden)

    D. Channei

    2013-01-01

    Full Text Available Cerium dioxide (CeO2 thin films with varying Ce concentrations (0.1 to 0.9 M, metal basis were deposited on soda-lime-silica glass substrates using spin coating. It was found that all films exhibited the cubic fluorite structure after annealing at 500°C for 5 h. The laser Raman microspectroscopy and GAXRD analyses revealed that increasing concentrations of Ce resulted in an increase in the degree of crystallinity. FIB and FESEM images confirmed the laser Raman and GAXRD analyses results owing to the predicted increase in film thickness with increasing Ce concentration. However, porosity and shrinkage (drying cracking of the films also increased significantly with increasing Ce concentrations. UV-VIS spectrophotometry data showed that the transmission of the films decreased with increasing Ce concentrations due to the increasing crack formation. Furthermore, a red shift was observed with increasing Ce concentrations, which resulted in a decrease in the optical indirect band gap.

  4. Investigating the interfacial dynamics of thin films

    Science.gov (United States)

    Rosenbaum, Aaron W.

    This thesis probes the interfacial dynamics and associated phenomena of thin films. Surface specific tools were used to study the self-assembly of alkanethiols, the mono- and bilayer dynamics of SF6, and the surface motion of poly(methyl methacrylate). Non-pertubative helium atom scattering was the principal technique used to investigate these systems. A variety of other complementary tools, including scanning tunneling microscopy, electron diffraction, Auger spectroscopy, atomic force microscopy, and ellipsometry were used in tandem with the neutral atom scattering studies. Controlling the spontaneous assembly of alkanethiols on Au(111) requires a better fundamental understanding of the adsorbate-adsorbate and substrate-adsorbate interactions. Our characterization focused on two key components, the surface structure and adsorbate vibrations. The study indicates that the Au(111) reconstruction plays a larger role than anticipated in the low-density phase of alkanethiol monolayers. A new structure is proposed for the 1-decanethiol monolayer that impacts the low-energy vibrational mode. Varying the alkane chain lengths imparts insight into the assembly process via characterization of a dispersionless phonon mode. Studies of SF6 physisorbed on Au(111) bridge surface research on rare gas adsorbates with complicated dynamical organic thin films. Mono- and bilayer coverages of SF6/Au(111) were studied at cryogenic temperatures. Our experiments probed the surface properties of SF6 yielding insights into substrate and coverage effects. The study discovered a dispersionless Einstein oscillation with multiple harmonic overtones. A second layer of SF6 softened the mode, but did not show any indications of bulk or cooperative interactions. The vibrational properties of SF 6 showed both striking similarities and differences when compared with physisorbed rare gases. Lastly, this thesis will discuss studies of thin film poly(methyl methacrylate) on Si. The non-pertubative and

  5. Theoretical investigation of the thermodynamic properties of metallic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)

    2015-05-29

    The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.

  6. Theoretical investigation of the thermodynamic properties of metallic thin films

    International Nuclear Information System (INIS)

    The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks

  7. Thin-liquid-film evaporation at contact line

    Institute of Scientific and Technical Information of China (English)

    Hao WANG; Zhenai PAN; Zhao CHEN

    2009-01-01

    When a liquid wets a solid wall, the extended meniscus near the contact line may be divided into three regions: a nonevaporating region, where the liquid is adsorbed on the wall; a transition region or thin-film region, where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region, where capillary forces dominate. The thin liquid film, with thickness from nanometers up to micrometers, covering the transition region and part of intrinsic meniscus, is gaining interest due to its high heat transfer rates. In this paper, a review was made of the researches on thin-liquid-film evaporation. The major characteristics of thin film, thin-film modeling based on continuum theory, simulations based on molecular dynamics, and thin-film profile and temperature measurements were summarized.

  8. Metallic Thin-Film Bonding and Alloy Generation

    Science.gov (United States)

    Fryer, Jack Merrill (Inventor); Campbell, Geoff (Inventor); Peotter, Brian S. (Inventor); Droppers, Lloyd (Inventor)

    2016-01-01

    Diffusion bonding a stack of aluminum thin films is particularly challenging due to a stable aluminum oxide coating that rapidly forms on the aluminum thin films when they are exposed to atmosphere and the relatively low meting temperature of aluminum. By plating the individual aluminum thin films with a metal that does not rapidly form a stable oxide coating, the individual aluminum thin films may be readily diffusion bonded together using heat and pressure. The resulting diffusion bonded structure can be an alloy of choice through the use of a carefully selected base and plating metals. The aluminum thin films may also be etched with distinct patterns that form a microfluidic fluid flow path through the stack of aluminum thin films when diffusion bonded together.

  9. Pulsed laser deposition of pepsin thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kecskemeti, G. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary)]. E-mail: kega@physx.u-szeged.hu; Kresz, N. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Smausz, T. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Hopp, B. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Nogradi, A. [Department of Ophthalmology, University of Szeged, H-6720, Szeged, Koranyi fasor 10-11 (Hungary)

    2005-07-15

    Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ({lambda} = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm{sup 2}. The pressure in the PLD chamber was 2.7 x 10{sup -3} Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm{sup 2}. The protein digesting capacity of the transferred pepsin was tested by adapting a modified 'protein cube' method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

  10. Orthogonal Thin Film Photovoltaics on Vertical Nanostructures.

    Science.gov (United States)

    Ahnood, Arman; Zhou, H; Suzuki, Y; Sliz, R; Fabritius, T; Nathan, Arokia; Amaratunga, G A J

    2015-12-01

    Decoupling paths of carrier collection and illumination within photovoltaic devices is one promising approach for improving their efficiency by simultaneously increasing light absorption and carrier collection efficiency. Orthogonal photovoltaic devices are core-shell type structures consisting of thin film photovoltaic stack on vertical nanopillar scaffolds. These types of devices allow charge collection to take place in the radial direction, perpendicular to the path of light in the vertical direction. This approach addresses the inherently high recombination rate of disordered thin films, by allowing semiconductor films with minimal thicknesses to be used in photovoltaic devices, without performance degradation associated with incomplete light absorption. This work considers effects which influence the performance of orthogonal photovoltaic devices. Illumination non-uniformity as light travels across the depth of the pillars, electric field enhancement due to the nanoscale size and shape of the pillars, and series resistance due to the additional surface structure created through the use of pillars are considered. All of these effects influence the operation of orthogonal solar cells and should be considered in the design of vertically nanostructured orthogonal photovoltaics.

  11. Stripe glasses in ferromagnetic thin films

    Science.gov (United States)

    Principi, Alessandro; Katsnelson, Mikhail I.

    2016-02-01

    Domain walls in magnetic multilayered systems can exhibit a very complex and fascinating behavior. For example, the magnetization of thin films of hard magnetic materials is in general perpendicular to the thin-film plane, thanks to the strong out-of-plane anisotropy, but its direction changes periodically, forming an alternating spin-up and spin-down stripe pattern. The latter is stabilized by the competition between the ferromagnetic coupling and dipole-dipole interactions, and disappears when a moderate in-plane magnetic field is applied. It has been suggested that such a behavior may be understood in terms of a self-induced stripe glassiness. In this paper we show that such a scenario is compatible with the experimental findings. The strong out-of-plane magnetic anisotropy of the film is found to be beneficial for the formation of both stripe-ordered and glassy phases. At zero magnetic field the system can form a glass only in a narrow interval of fairly large temperatures. An in-plane magnetic field, however, shifts the glass transition towards lower temperatures, therefore enabling it at or below room temperature. In good qualitative agreement with the experimental findings, we show that a moderate in-plane magnetic field of the order of 50 mT can lead to the formation of defects in the stripe pattern, which sets the onset of the glass transition.

  12. Memristive switching in vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Buerger, Danilo; John, Varun; Kovacs, Gyoergy; Skorupa, Ilona; Helm, Manfred; Schmidt, Heidemarie [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2011-07-01

    Memristive devices exhibit an improved performance at ultra-small scales. The microscopic model for memristive behavior in oxide nanostructures often depends on the distribution of oxygen vacancies and is determined by the cation species. In 2008 HP presented the first bipolar TiO2-based memristor for resistive applications, where the drift of oxygen vacancies causes a change in the resistance of ultrathin TiO2 films which can be locally modified by ion implantation. We prepared vanadium dioxide (VO2) thin films with the reversible metal-insulator phase transition at the thermochromic switching temperature of around 340 K by pulsed laser deposition on (0001)-sapphire substrates and analyzed the electric-pulse-induced thermochromic switching in the VO2 gap region at room temperature due to local heating. As a result, we find the typical pinched hysteresis loop of a memristor, a repeatable switching behavior for billions of voltage pulses and switching times shorter than 50 ns in VO2 thin films.

  13. Thin-film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1986-08-01

    The major objective of this work was to demonstrate CdTe devices grown by chemical vapor deposition (CVD) with a total area greater than 1 cm2 and photovoltic efficiencies of at least 13%. During the period covered, various processing steps were investigated for the preparation of thin-film CdTe heterojunction solar cells of the inverted configuration. Glass coated with fluorine-doped tin oxide was used as the substrate. Thin-film heterojunction solar cells were prepared by depositing p-CdTe films on substrates using CVD and close-spaced sublimation (CSS). Cells prepared from CSS CdTe usually have a higher conversion efficiency than those prepared from CVD CdTe, presumably due to the chemical interaction between CdS and CdTe at the interface during the CVD process. The best cell, about 1.2 sq cm in area, had an AM 1.5 (global) efficiency of 10.5%, and further improvements are expected by optimizing the process parameters.

  14. Epitaxially-Grown Europium-Doped Barium Titanate Films on Various Substrates for Red Emission.

    Science.gov (United States)

    Hwang, Kyu-Seog; Jeon, Young-Sun; Lee, Young-Hwan; Hwangbo, Seung; Kim, Jin-Tae

    2015-10-01

    Intense red photoluminescence under ultraviolet excitation was observed in epitaxially-grown europium-doped perovskite BaTiO3 thin films deposited on the SrTiO3 (100), MgO (100) and sapphire (0001) substrates using metal carboxylate complexes. Precursor films prepared by spin coating were pyrolyzed at 250 °C for 120 min in argon, followed by final annealing at 850 °C for 60 min in argon. Crystallinity and epitaxy of the films were analyzed by X-ray diffraction θ-2θ scan and pole-figure analysis. Photoluminescence of the thin films at room temperature under 254 nm was confirmed by a fluorescent spectrophotometer. The obtained epitaxial BaTiO3 thin films on the SrTiO3 (100) and MgO (100) substrates show an intense red-emission lines at 615 nm corresponding to the (5)D0 --> (7)F2 transitions on Eu(3+) with broad bands at 595 and 650 nm. PMID:26726427

  15. High Performance Flexible Piezoelectric Nanogenerators based on BaTiO3 Nanofibers in Different Alignment Modes.

    Science.gov (United States)

    Yan, Jing; Jeong, Young Gyu

    2016-06-22

    Piezoelectric nanogenerators, harvesting energy from mechanical stimuli in our living environments, hold great promise to power sustainable self-sufficient micro/nanosystems and mobile/portable electronics. BaTiO3 as a lead-free material with high piezoelectric coefficient and dielectric constant has been widely examined to realize nanogenerators, capacitors, sensors, etc. In this study, polydimethylsiloxane (PDMS)-based flexible composites including BaTiO3 nanofibers with different alignment modes were manufactured and their piezoelectric performance was examined. For the study, BaTiO3 nanofibers were prepared by an electrospinning technique utilizing a sol-gel precursor and following calcination process, and they were then aligned vertically or horizontally or randomly in PDMS matrix-based nanogenerators. The morphological structures of BaTiO3 nanofibers and their nanogenerators were analyzed by using SEM images. The crystal structures of the nanogenerators before and after poling were characterized by X-ray diffraction. The dielectric and piezoelectric properties of the nanogenerators were investigated as a function of the nanofiber alignment mode. The nanogenerator with BaTiO3 nanofibers aligned vertically in the PDMS matrix sheet achieved high piezoelectric performance of an output power of 0.1841 μW with maximum voltage of 2.67 V and current of 261.40 nA under a low mechanical stress of 0.002 MPa, in addition to a high dielectric constant of 40.23 at 100 Hz. The harvested energy could thus power a commercial LED directly or be stored into capacitors after rectification. PMID:27237223

  16. High Performance Flexible Piezoelectric Nanogenerators based on BaTiO3 Nanofibers in Different Alignment Modes.

    Science.gov (United States)

    Yan, Jing; Jeong, Young Gyu

    2016-06-22

    Piezoelectric nanogenerators, harvesting energy from mechanical stimuli in our living environments, hold great promise to power sustainable self-sufficient micro/nanosystems and mobile/portable electronics. BaTiO3 as a lead-free material with high piezoelectric coefficient and dielectric constant has been widely examined to realize nanogenerators, capacitors, sensors, etc. In this study, polydimethylsiloxane (PDMS)-based flexible composites including BaTiO3 nanofibers with different alignment modes were manufactured and their piezoelectric performance was examined. For the study, BaTiO3 nanofibers were prepared by an electrospinning technique utilizing a sol-gel precursor and following calcination process, and they were then aligned vertically or horizontally or randomly in PDMS matrix-based nanogenerators. The morphological structures of BaTiO3 nanofibers and their nanogenerators were analyzed by using SEM images. The crystal structures of the nanogenerators before and after poling were characterized by X-ray diffraction. The dielectric and piezoelectric properties of the nanogenerators were investigated as a function of the nanofiber alignment mode. The nanogenerator with BaTiO3 nanofibers aligned vertically in the PDMS matrix sheet achieved high piezoelectric performance of an output power of 0.1841 μW with maximum voltage of 2.67 V and current of 261.40 nA under a low mechanical stress of 0.002 MPa, in addition to a high dielectric constant of 40.23 at 100 Hz. The harvested energy could thus power a commercial LED directly or be stored into capacitors after rectification.

  17. Overview and Challenges of Thin Film Solar Electric Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  18. Networking Behavior in Thin Film and Nanostructure Growth Dynamics

    OpenAIRE

    Yuksel, Murat; Karabacak, Tansel; Guclu, Hasan

    2007-01-01

    Thin film coatings have been essential in development of several micro and nano-scale devices. To realize thin film coatings various deposition techniques are employed, each yielding surface morphologies with different characteristics of interest. Therefore, understanding and control of the surface growth is of great interest. In this paper, we devise a novel network-based modeling of the growth dynamics of such thin films and nano-structures. We specifically map dynamic steps taking place du...

  19. Polarized Neutron Reflectivity Simulation of Ferromagnet/ Antiferromagnet Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Yeon; Lee, Jeong Soo

    2008-02-15

    This report investigates the current simulating and fitting programs capable of calculating the polarized neutron reflectivity of the exchange-biased ferromagnet/antiferromagnet magnetic thin films. The adequate programs are selected depending on whether nonspin flip and spin flip reflectivities of magnetic thin films and good user interface are available or not. The exchange-biased systems such as Fe/Cr, Co/CoO, CoFe/IrMn/Py thin films have been simulated successfully with selected programs.

  20. Polycrystalline-thin-film thermophotovoltaic cells

    Science.gov (United States)

    Dhere, Neelkanth G.

    1996-02-01

    Thermophotovoltaic (TPV) cells convert thermal energy to electricity. Modularity, portability, silent operation, absence of moving parts, reduced air pollution, rapid start-up, high power densities, potentially high conversion efficiencies, choice of a wide range of heat sources employing fossil fuels, biomass, and even solar radiation are key advantages of TPV cells in comparison with fuel cells, thermionic and thermoelectric convertors, and heat engines. The potential applications of TPV systems include: remote electricity supplies, transportation, co-generation, electric-grid independent appliances, and space, aerospace, and military power applications. The range of bandgaps for achieving high conversion efficiencies using low temperature (1000-2000 K) black-body or selective radiators is in the 0.5-0.75 eV range. Present high efficiency convertors are based on single crystalline materials such as In1-xGaxAs, GaSb, and Ga1-xInxSb. Several polycrystalline thin films such as Hg1-xCdxTe, Sn1-xCd2xTe2, and Pb1-xCdxTe, etc., have great potential for economic large-scale applications. A small fraction of the high concentration of charge carriers generated at high fluences effectively saturates the large density of defects in polycrystalline thin films. Photovoltaic conversion efficiencies of polycrystalline thin films and PV solar cells are comparable to single crystalline Si solar cells, e.g., 17.1% for CuIn1-xGaxSe2 and 15.8% for CdTe. The best recombination-state density Nt is in the range of 10-15-10-16 cm-3 acceptable for TPV applications. Higher efficiencies may be achieved because of the higher fluences, possibility of bandgap tailoring, and use of selective emitters such as rare earth oxides (erbia, holmia, yttria) and rare earth-yttrium aluminium garnets. As compared to higher bandgap semiconductors such as CdTe, it is easier to dope the lower bandgap semiconductors. TPV cell development can benefit from the more mature PV solar cell and opto

  1. Applications of thin-film photovoltaics for space

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The authors discuss the potential applications of thin-film polycrystalline and amorphous cells for space. There have been great advances in thin-film solar cells for terrestrial applications. Transfer of this technology to space applications could result in ultra low-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper indium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon arrays. The possibility of using thin-film multi-bandgap cascade solar cells is discussed.

  2. Thin-Film Photovoltaics: Status and Applications to Space Power

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The potential applications of thin film polycrystalline and amorphous cells for space are discussed. There have been great advances in thin film solar cells for terrestrial applications; transfer of this technology to space applications could result in ultra low weight solar arrays with potentially large gains in specific power. Recent advances in thin film solar cells are reviewed, including polycrystalline copper iridium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon alloys. The possibility of thin film multi bandgap cascade solar cells is discussed.

  3. Physics of thin films advances in research and development

    CERN Document Server

    Hass, Georg; Vossen, John L

    2013-01-01

    Physics of Thin Films: Advances in Research and Development, Volume 12 reviews advances that have been made in research and development concerning the physics of thin films. This volume covers a wide range of preparative approaches, physics phenomena, and applications related to thin films. This book is comprised of four chapters and begins with a discussion on metal coatings and protective layers for front surface mirrors used at various angles of incidence from the ultraviolet to the far infrared. Thin-film materials and deposition conditions suitable for minimizing reflectance changes with

  4. Growth and Characterization of Epitaxial Oxide Thin Films

    OpenAIRE

    Garg, Ashish

    2001-01-01

    Epitaxial oxide thin films are used in many technologically important device applications. This work deals with the deposition and characterization of epitaxial WO3 and SrBi2Ta2O9 (SBT) thin films on single crystal oxide substrates. WO3 thin films were chosen as a subject of study because of recent findings of superconductivity at surfaces and twin boundaries in the bulk form of this oxide. Highly epitaxial thin films would be desirable in order to be able to create a device withi...

  5. Design and Simulation of the Thin Film Pulse Transformer

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-yuan; SHI Yu; WEN Qi-ye

    2005-01-01

    A new thin film pulse transformer for using in ISND and ADSL systems has been designed based on a domain wall pinning model, the parameters of nano-magnetic thin film such as permeability and coercivity can be calculated. The main properties of the thin film transformer including the size,parallel inductance, Q value and turn ratio have been simulated and optimized. Simulation results show that the thin film transformer can be fairly operated in a frequency range of 0. 001~20 MHz.

  6. Sputtering materials for VLSI and thin film devices

    CERN Document Server

    Sarkar, Jaydeep

    2010-01-01

    An important resource for students, engineers and researchers working in the area of thin film deposition using physical vapor deposition (e.g. sputtering) for semiconductor, liquid crystal displays, high density recording media and photovoltaic device (e.g. thin film solar cell) manufacturing. This book also reviews microelectronics industry topics such as history of inventions and technology trends, recent developments in sputtering technologies, manufacturing steps that require sputtering of thin films, the properties of thin films and the role of sputtering target performance on overall p

  7. Characterizations of photoconductivity of graphene oxide thin films

    Directory of Open Access Journals (Sweden)

    Shiang-Kuo Chang-Jian

    2012-06-01

    Full Text Available Characterizations of photoresponse of a graphene oxide (GO thin film to a near infrared laser light were studied. Results showed the photocurrent in the GO thin film was cathodic, always flowing in an opposite direction to the initial current generated by the preset bias voltage that shows a fundamental discrepancy from the photocurrent in the reduced graphene oxide thin film. Light illumination on the GO thin film thus results in more free electrons that offset the initial current. By examining GO thin films reduced at different temperatures, the critical temperature for reversing the photocurrent from cathodic to anodic was found around 187°C. The dynamic photoresponse for the GO thin film was further characterized through the response time constants within the laser on and off durations, denoted as τon and τoff, respectively. τon for the GO thin film was comparable to the other carbon-based thin films such as carbon nanotubes and graphenes. τoff was, however, much larger than that of the other's. This discrepancy was attributable to the retardation of exciton recombination rate thanks to the existing oxygen functional groups and defects in the GO thin films.

  8. Role of asphaltenes in stabilizing thin liquid emulsion films.

    Science.gov (United States)

    Tchoukov, Plamen; Yang, Fan; Xu, Zhenghe; Dabros, Tadeusz; Czarnecki, Jan; Sjöblom, Johan

    2014-03-25

    Drainage kinetics, thickness, and stability of water-in-oil thin liquid emulsion films obtained from asphaltenes, heavy oil (bitumen), and deasphalted heavy oil (maltenes) diluted in toluene are studied. The results show that asphaltenes stabilize thin organic liquid films at much lower concentrations than maltenes and bitumen. The drainage of thin organic liquid films containing asphaltenes is significantly slower than the drainage of the films containing maltenes and bitumen. The films stabilized by asphaltenes are much thicker (40-90 nm) than those stabilized by maltenes (∼10 nm). Such significant variation in the film properties points to different stabilization mechanisms of thin organic liquid films. Apparent aging effects, including gradual increase of film thickness, rigidity of oil/water interface, and formation of submicrometer size aggregates, were observed for thin organic liquid films containing asphaltenes. No aging effects were observed for films containing maltenes and bitumen in toluene. The increasing stability and lower drainage dynamics of asphaltene-containing thin liquid films are attributed to specific ability of asphaltenes to self-assemble and form 3D network in the film. The characteristic length of stable films is well beyond the size of single asphaltene molecules, nanoaggregates, or even clusters of nanoaggregates reported in the literature. Buildup of such 3D structure modifies the rheological properties of the liquid film to be non-Newtonian with yield stress (gel like). Formation of such network structure appears to be responsible for the slower drainage of thin asphaltenes in toluene liquid films. The yield stress of liquid film as small as ∼10(-2) Pa is sufficient to stop the drainage before the film reaches the critical thickness at which film rupture occurs. PMID:24564447

  9. Atomic Structure Control of Silica Thin Films on Pt(111)

    KAUST Repository

    Crampton, Andrew S

    2015-05-27

    Metal oxide thin films grown on metal single crystals are commonly used to model heterogeneous catalyst supports. The structure and properties of thin silicon dioxide films grown on metal single crystals have only recently been thoroughly characterized and their spectral properties well established. We report the successful growth of a three- dimensional, vitreous silicon dioxide thin film on the Pt(111) surface and reproduce the closed bilayer structure previously reported. The confirmation of the three dimensional nature of the film is unequivocally shown by the infrared absorption band at 1252 cm−1. Temperature programmed desorption was used to show that this three-dimensional thin film covers the Pt(111) surface to such an extent that its application as a catalyst support for clusters/nanoparticles is possible. The growth of a three-dimensional film was seen to be directly correlated with the amount of oxygen present on the surface after the silicon evaporation process. This excess of oxygen is tentatively attributed to atomic oxygen being generated in the evaporator. The identification of atomic oxygen as a necessary building block for the formation of a three-dimensional thin film opens up new possibilities for thin film growth on metal supports, whereby simply changing the type of oxygen enables thin films with different atomic structures to be synthesized. This is a novel approach to tune the synthesis parameters of thin films to grow a specific structure and expands the options for modeling common amorphous silica supports under ultra high vacuum conditions.

  10. Electrical Resistance Tomography of Conductive Thin Films

    CERN Document Server

    Cultrera, Alessandro

    2016-01-01

    The Electrical Resistance Tomography (ERT) technique is applied to the measurement of sheet conductance maps of both uniform and patterned conductive thin films. Images of the sheet conductance spatial distribution, and local conductivity values are obtained. Test samples are tin oxide films on glass substrates, with electrical contacts on the sample boundary, some samples are deliberately patterned in order to induce null conductivity zones of known geometry while others contain higher conductivity inclusions. Four-terminal resistance measurements among the contacts are performed with a scanning setup. The ERT reconstruction is performed by a numerical algorithm based on the total variation regularization and the L-curve method. ERT correctly images the sheet conductance spatial distribution of the samples. The reconstructed conductance values are in good quantitative agreement with independent measurements performed with the van der Pauw and the four-point probe methods.

  11. Levan nanostructured thin films by MAPLE assembling.

    Science.gov (United States)

    Sima, Felix; Mutlu, Esra Cansever; Eroglu, Mehmet S; Sima, Livia E; Serban, Natalia; Ristoscu, Carmen; Petrescu, Stefana M; Oner, Ebru Toksoy; Mihailescu, Ion N

    2011-06-13

    Synthesis of nanostructured thin films of pure and oxidized levan exopolysaccharide by matrix-assisted pulsed laser evaporation is reported. Solutions of pure exopolysaccharides in dimethyl sulfoxide were frozen in liquid nitrogen to obtain solid cryogenic pellets that have been used as targets in pulsed laser evaporation experiments with a KrF* excimer source. The expulsed material was collected and assembled onto glass slides and Si wafers. The contact angle studies evidenced a higher hydrophilic behavior in the case of oxidized levan structures because of the presence of acidic aldehyde-hydrogen bonds of the coating formed after oxidation. The obtained films preserved the base material composition as confirmed by Fourier transform infrared spectroscopy. They were compact with high specific surface areas, as demonstrated by scanning electron and atomic force microscopy investigations. In vitro colorimetric assays revealed a high potential for cell proliferation for all coatings with certain predominance for oxidized levan. PMID:21520921

  12. Separation Efficiency of Thin-film Evaporators

    Institute of Scientific and Technical Information of China (English)

    R.Billet

    2004-01-01

    The recovery of contaminants and useful substances from liquid wastes, the purification of production effluents and the separation of thermally instable mixtures are some of the multivarious applications of thin-film distillors in many processes of the chemical and allied industries and of the food industries. In a study carried out in pilot plants with distillation test systems there was found a good agreement between the experimental separation results and those obtained by computing with a theorectical model; the latter is based on the assumption of phase equilibrium between the vapour formed on an infinitely small element of area in a liquid film of any given concentric periphery of the vertically arranged evaporator. These tests were perfomed under various phase loads.

  13. Modelling the tribology of thin film interfaces

    CERN Document Server

    Zugic, R

    2000-01-01

    substrate). Within each group of simulations, three lubricant film thicknesses are studied to examine the effect of varying lubricant thickness. Statistical data are collected from each simulation and presented in this work. Via these data, together with the evolution, of atomic and molecular configurations, a very detailed picture of the properties of this thin film interface is presented. In particular, we conclude that perfluoropolyether lubricant forms distinct molecular layers when confined between two substrates, the rate of heat generation under shearing conditions typical of those in a head-disk interface is insufficient for thermal mechanisms to result directly in lubricant degradation, and mechanical stresses attained in the head-disk interface are unlikely to result in any significant degree of lubricant degradation. This thesis examines the tribology of a head-disk interface in an operating hard disk drive via non-equilibrium molecular dynamics computer simulations. The aim of this work is to deri...

  14. Analysis on mechanism of thin film lubrication

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaohui; LUO Jianbin; HUANG Zhiqiang

    2005-01-01

    It is an important concern to explore the properties and principles of lubrication at nano or molecularscale. For a long time, measurement apparatus for filmthickness of thin film lubrication (TFL) at nano scale havebeen devised on the basis of superthin interferometry technique. Many experiments were carried out to study the lubrication principles of TFL by taking advantages of aforementioned techniques, in an attempt to unveil the mechanism of TFL. Comprehensive experiments were conducted to explore the distinctive characteristics of TFL. Results show that TFL is a distinctive lubrication state other than any known lubrication ones, and serves as a bridge between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL). Two main influence factors of TFL are the solid surface effects and the molecular properties of the lubricant, whose combination effects result in alignment of liquid molecules near the solid surfaces and subsequently lubrication with ordered film emerged. Results of theoretical analysis considering microstructure are consistent with experimental outcomes, thus validating the proposed mechanism.

  15. Thin-film optical shutter. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  16. Fabrication of Optical Tunable Helical Thin Films

    Institute of Scientific and Technical Information of China (English)

    Linxin Hu; Peng Wang; Xingyang Wan; Shaoji Jiang

    2012-01-01

    Circular polarization selection of light is an important property of helical micro-nanostructure. The helical thin films fabricated by glancing angle deposition can provide both circular polarization selection and wavelength tuning in this work. Their selective transmissions were depicted in calculations and experiments. The wave- length tuning mechanism was revealed as the relationship between peak wavelength and deposition parameters. Therefore, tunable circular polarization components can be designed according to the mechanism mentioned above and fabricated by glancing angle deposition techniques. Potential applications include tunable optical filters, optical pulse-shapers, biosensors etc.

  17. Stable localized patterns in thin liquid films

    Science.gov (United States)

    Deissler, Robert J.; Oron, Alexander

    1992-01-01

    A two-dimensional nonlinear evolution equation is studied which describes the three-dimensional spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. It is shown that the equation has a Liapunov functional, and this fact is exploited to demonstrate that the Marangoni effect can stabilize the destabilizing effect of gravity (the Rayleigh-Taylor instability), allowing for the existence of stable localized axisymmetric solutions for a wide range of parameter values. Various properties of these structures are discussed.

  18. Thin Film Photovoltaics: Markets and Industry

    OpenAIRE

    Arnulf Jäger-Waldau

    2012-01-01

    Since 2000, total PV production increased almost by two orders of magnitude, with a compound annual growth rate of over 52%. The most rapid growth in annual cell and module production over the last five years could be observed in Asia, where China and Taiwan together now account for about 60% of worldwide production. Between 2005 and 2009, thin film production capacity and volume increased more than the overall industry but did not keep up in 2010 and 2011 due to the rapid price decline for s...

  19. Optical and Nonlinear Optical Response of Light Sensor Thin Films

    OpenAIRE

    Weisz, S.Z.; O. Resto; Fonseca, F; Fernandez, L. F.E.; Vikhnin, V. S.; O. Vasquez; A. J. Rua; H. Liu

    2005-01-01

    For potential ultrafast optical sensor application, both VO2 thin films and nanocomposite crystal-Si enriched SiO2 thin films grown on fused quartz substrates were successfully prepared using pulsed laser deposition (PLD) and RF co-sputtering techniques. In photoluminescence (PL) measurement c-Si/SiO2 film contains nanoparticles of crystal Si exhibits strong red emission with the band maximum ranging from 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremely intense ...

  20. Capillary instabilities in thin films. II. Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Srolovitz, D.J.; Safran, S.A.

    1986-07-01

    We consider the kinetic evolution of perturbations to thin films. Since all small (nonsubstrate intersecting) perturbations to the film surface decay, we consider the evolution of large perturbations, in the form of a single hole which exposes the substrate. For large holes, the hole radius increases at a constant rate under the assumption of evaporation/condensation kinetics. When the dominant transport mode is surface diffusion, large holes grow with a rate proportional to t/sup -3/4/ (log/sup 3/(t/ rho/sup 4//sub c/)). Small holes with a radii less than rho/sub c/ shrink, where rho/sub c/ is the film thickness divided by the tangent of the equilibrium wetting angle. The growth of these holes eventually leads to hole impingement which ruptures the film, creating a set of disconnected islands. The relaxation time for these islands to go to their equilibrium shape and size (rho/sub eq/) scales as rho/sup 2//sub eq/ or rho/sup 4//sub eq/ for evaporation/condensation or surface diffusion kinetics, respectively.

  1. High Tc thin film and device development

    Energy Technology Data Exchange (ETDEWEB)

    Betts, K.; Burbank, M.B.; Cragg, A.; Fife, A.A.; Kubik, P.R.; Lee, S.; Chaklader, A.C.D.; Roemer, G.; Heinrich, B.; Chrzanowski, J.

    1989-03-01

    Thin films of the high Tc superconductor YBa/sub 2/Cu/sub 3/O/sub y/ have been deposited on various substrates by diode and magnetron sputtering using bulk sintered targets. These films have been analyzed by a variety of methods - SEM, X-rays, Electron Beam Microprobe, Mass Spectrometry and Raman Spectroscopy. The stoichiometries of the films have been measured as a function of the radial position from the centre of the sputtered beam at a fixed target-substrate distance. Patterning of the films has been carried out to form planar structures such as strip lines, microbridges and RF SQUIDs. DC current-voltage characteristics of the microbridges were measured as a function of temperature. RF SQUID behaviour has been observed for single loop devices and their properties established at 4.2 K and higher temperatures. Flux locked noise spectra with a 1/f noise power response were recorded in the frequency range 0.01 to approx.100 Hz. RF SQUID signals have been observed for temperatures up to 55 K.

  2. Phase transitions in pure and dilute thin ferromagnetic films

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1983-10-01

    The mean-field model of a thin ferromagnetic film where the nearest-neighbor exchange coupling in surface layers can be different from that inside the film is considered. The phase diagram, equations for the second-order phase-transition lines, and the spontaneous magnetization profiles near the phase transitions are given. It is shown that there is no extra-ordinary transition in a thin film. If the thickness of the film tends to infinity the well-known results for the mean-field model of a semi-infinite ferromagnet are obtained. The generalization for disordered dilute thin ferromagnetic films and semi-infinite ferromagnets is also given.

  3. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stöber, Laura, E-mail: laura.stoeber@tuwien.ac.at; Patocka, Florian, E-mail: florian.patocka@tuwien.ac.at; Schneider, Michael, E-mail: michael.schneider@tuwien.ac.at; Schmid, Ulrich, E-mail: ulrich.e366.schmid@tuwien.ac.at [Institute of Sensor and Actuator Systems, TU Wien, Gußhausstraße 27-29, A-1040 Vienna (Austria); Konrath, Jens Peter, E-mail: jenspeter.konrath@infineon.com; Haberl, Verena, E-mail: verena.haberl@infineon.com [Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)

    2016-03-15

    In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo{sub 2}N) thin films. Various argon and nitrogen gas compositions are applied for thin film synthetization, and the amount of nitrogen incorporation is determined by Auger measurements. Furthermore, effusion measurements identifying the binding conditions of the nitrogen in the thin film are performed up to 1000 °C. These results are in excellent agreement with film stress and scanning electron microscope analyses, both indicating stable film properties up to annealing temperatures of 500 °C.

  4. Calculation of Specific Heat for Aluminium Thin Films

    Institute of Scientific and Technical Information of China (English)

    LU Yao; SONG Qing-Lin; XIA Shan-Hong

    2005-01-01

    @@ We employ Prasher's non-dimensional form to analyse the size effects on specific heat of Al thin films. Compared the calculation results of pure aluminium film with the experimental data, it is found that the reduction of phonon states is not the main reason of the size effect on the specific heat Al thin films with thickness from 10hm to 370nm. However, the Al thin film in air usually has an oxidation layer and the specific heat of the layer is smaller than Al. By including the contribution of the oxidation layer to the thin-film specific heat, the calculation results are much closer to the experimental data. This may be a possible reason of the size effects on specific heat of Al thin films.

  5. PREPARATION OF POLYIMIDE-BaTiO3 HYBRID FILMS BY A DISPERSION PROCESS AND THEIR MICROSTRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Yue-sheng Li; Yue-jin Tong; Kai Jing; Meng-xian Ding

    2001-01-01

    Barium titanate (BaTiO3) powders with particle sizes of 30~50 nm were prepared from barium stearate, titanium alkoxides and stearic acid by stearic acid-gel method. Dispersing the agglomerate of BaTiO3 nanoparticles into poly(amic acid) solution followed by curing led to the formation of polyimide hybrid films. The hybrid films were transparent and well distributed with BaTiO3 nanoparticles when the BaTiO3 content was less than 1 wt%. Highly loaded hybrid film containing 30 wt % BaTiO3 was tough, had a smooth surface and possessed much higher dielectric and piezoelectric constants than the parent polyimide.

  6. CLSM and UV-VIS researches on polyoxadiazoles thin films

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2012-06-01

    Full Text Available Purpose: The purpose of this paper was to analyse the surface morphology and optical properties of polyoxadiazoles thin films.Design/methodology/approach: A few different conducting polymers were dissolved in N-methyl-2-pyrrolid(inone. Then the solutions were deposited on a glass substrate by spin coating method with a different spin rate. Changes in surface topography and optical properties were observed. A confocal laser scanning microscope CLSM Zeiss LSM 5 Exciter has been used. Photos have been taken from area of 120 x 120 microns.Findings: The analysis of images and spectra has confirmed that the quality of thin films depends upon the used polymers. It was also observed that the parameters of the spin coating method have significant effect on the morphology and the optical properties. The spin rate has got a strong impact on them.Research limitations/implications: The morphology and optical properties of polyoxadiazoles thin films has been described. This paper include description how the spin rate influence on the polymer thin films. In order to use a polymer thin film in photovoltaics or optoelectronics it must have a high internal transmission density. Further research of polymer thin films are recommended.Practical implications: The spin coating method allows to deposit a uniform thin films. It is important to know how the spin rate influence on the thin films properties. It is also important to find a new use for this group of material engineering in photovoltaic or optoelectronics devices.Originality/value: The good properties of thin films make them suitable for various applications. The value of this paper is defining the optimal parameters of spin-coating technology for polyoxadiazoles thin films. The results allow the choosing optimal parameters of the deposition process. Spin coating is a very good method to obtain thin films which are obligated to have the same thickness over the whole surface.

  7. Metal nanoparticles for thin film solar cells

    DEFF Research Database (Denmark)

    Gritti, Claudia

    Among the different renewable ways to produce energy, photovoltaic cells have a big potential and the research is now focusing on getting higher efficiency and at the same time saving the manufacturing costs improving the performance of thin film solar cells. The spectral distribution in the infr......Among the different renewable ways to produce energy, photovoltaic cells have a big potential and the research is now focusing on getting higher efficiency and at the same time saving the manufacturing costs improving the performance of thin film solar cells. The spectral distribution...... the promotion of electrons from the valence band of the semiconductor. The photoemission would extend the spectral response of the photovoltaic device. Thus, NPs are placed at the metal/semiconductor interface (in order to exploit the localization characteristic of the LSP enhancement) and are used as active...... the solar cell structure (GaAs, SiO2, Si3N4, AZO/Cr), in order to investigate the LSP resonance and tune it to exploit it below the energy band gap of the semiconductor. EBL is a difficult technique when working by lift-off on critical size (20-50 nm) nanoparticles. The optimization of the process saw...

  8. Optical thin film metrology for optoelectronics

    Science.gov (United States)

    Petrik, Peter

    2012-12-01

    The manufacturing of optoelectronic thin films is of key importance, because it underpins a significant number of industries. The aim of the European joint research project for optoelectronic thin film characterization (IND07) in the European Metrology Research Programme of EURAMET is to develop optical and X-ray metrologies for the assessment of quality as well as key parameters of relevant materials and layer systems. This work is intended to be a step towards the establishment of validated reference metrologies for the reliable characterization, and the development of calibrated reference samples with well-defined and controlled parameters. In a recent comprehensive study (including XPS, AES, GD-OES, GD-MS, SNMS, SIMS, Raman, SE, RBS, ERDA, GIXRD), Abou-Ras et al. (Microscopy and Microanalysis 17 [2011] 728) demonstrated that most characterization techniques have limitations and bottle-necks, and the agreement of the measurement results in terms of accurate, absolute values is not as perfect as one would expect. This paper focuses on optical characterization techniques, laying emphasis on hardware and model development, which determine the kind and number of parameters that can be measured, as well as their accuracy. Some examples will be discussed including optical techniques and materials for photovoltaics, biosensors and waveguides.

  9. Antimony selenide thin-film solar cells

    Science.gov (United States)

    Zeng, Kai; Xue, Ding-Jiang; Tang, Jiang

    2016-06-01

    Due to their promising applications in low-cost, flexible and high-efficiency photovoltaics, there has been a booming exploration of thin-film solar cells using new absorber materials such as Sb2Se3, SnS, FeS2, CuSbS2 and CuSbSe2. Among them, Sb2Se3-based solar cells are a viable prospect because of their suitable band gap, high absorption coefficient, excellent electronic properties, non-toxicity, low cost, earth-abundant constituents, and intrinsically benign grain boundaries, if suitably oriented. This review surveys the recent development of Sb2Se3-based solar cells with special emphasis on the material and optoelectronic properties of Sb2Se3, the solution-based and vacuum-based fabrication process and the recent progress of Sb2Se3-sensitized and Sb2Se3 thin-film solar cells. A brief overview further addresses some of the future challenges to achieve low-cost, environmentally-friendly and high-efficiency Sb2Se3 solar cells.

  10. Critical misfit of epitaxial growth metallic thin films

    Institute of Scientific and Technical Information of China (English)

    LI Jian-Chen; LIU Wei; JIANG Qing

    2005-01-01

    The critical misfit of epitaxial growth metallic thin films fc was thermodynamically considered. It is found that there exists a competition between the energy of the misfit dislocation of film and non-coherent interface energy of film-substrate. Equilibrium between these energies was present at a critical atomic misfit fc. When the atomic misfit is larger than the critical value, epitaxial growth does not occur. The critical misfit of the epitaxial growth thin films can be predicted. The results show that fc is proportional to the non-coherent interface energy of the film-substrate, and inversely proportional to the elastic modulus and the thickness of the film.

  11. Polycystalline silicon thin films for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Christian Claus

    2012-01-15

    For the thin polycrystalline Si films fabricated with the aluminium-induced-layer-exchange (ALILE) process a good structural quality up to a layer-thickness value of 10 nm was determined. For 5 nm thick layers however after the layer exchange no closes poly-silicon film was present. In this case the substrate was covered with spherically arranged semiconductor material. Furthermore amorphous contributions in the layer could be determined. The electrical characterization of the samples at room temperature proved a high hole concentration in the range 10{sup 18} cm{sup -3} up to 9.10{sup 19} cm{sup -3}, which is influenced by the process temperature and the layer thickness. Hereby higher hole concentrations at higher process temperatures and thinner films were observed. Furthermore above 150-200 K a thermically activated behaviour of the electrical conductivity was observed. At lower temperatures a deviation of the measured characteristic from the exponential Arrhenius behaviour was determined. For low temperatures (below 20 K) the conductivity follows the behaviour {sigma}{proportional_to}[-(T{sub 0}/T){sup 1/4}]. The hole mobility in the layers was lowered by a passivation step, which can be explained by defect states at the grain boundaries. The for these very thin layers present situation was simulated in the framework of the model of Seto, whereby both the defect states at the grain boundaries (with an area density Q{sub t}) and the defect states at the interfaces (with an area density Q{sub it}) were regarded. By this the values Q{sub t}{approx}(3-4).10{sup 12} cm{sup -2} and Q{sub it}{approx}(2-5).10{sup 12} cm{sup -2} could be determined for these thin ALILE layers on quartz substrates. Additionally th R-ALILE process was studied, which uses the reverse precursor-layer sequence substrate/amorphous silicon/oxide/aluminium. Hereby two steps in the crystallization process of the R-ALILE process were found. First a substrate/Al-Si mixture/poly-Si layer structure

  12. The preparation and refractive index of BST thin films

    International Nuclear Information System (INIS)

    Radio-frequency magnetron sputtering technique is used to deposit Ba0.65Sr0.35TiO3 (BST) thin films on fused quartz substrates. In order to prepare the high-quality BST thin films, the crystallization and microstructure of the films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). More intense characteristic diffraction peaks and better crystallization can be observed in BST thin films deposited at 600 deg. C and subsequently annealed at 700 deg. C. The refractive index of the films is determined from the measured transmission spectra. The dependences of the refractive index on the deposition parameters of BST thin films are different. The refractive index of the films increases with the substrate temperature. At lower sputtering pressure, the refractive index increases from 1.797 to 2.197 with pressure increase. However, when the pressure increases up to 3.9 Pa, the refractive index reduces to 1.86. The oxygen to argon ratio also plays an important effect on the refractive index of the films. It has been found that the refractive index increases with increase in the ratio of oxygen to argon. The refractive index of BST thin films is strongly dependent on the annealing temperature, which also increases as the annealing temperature ascends. In a word, the refractive index of BST thin films is finally affected by the films' microstructure and texture

  13. Scalability of carbon-nanotube-based thin film transistors for flexible electronic devices manufactured using an all roll-to-roll gravure printing system

    Science.gov (United States)

    Koo, Hyunmo; Lee, Wookyu; Choi, Younchang; Sun, Junfeng; Bak, Jina; Noh, Jinsoo; Subramanian, Vivek; Azuma, Yasuo; Majima, Yutaka; Cho, Gyoujin

    2015-09-01

    To demonstrate that roll-to-roll (R2R) gravure printing is a suitable advanced manufacturing method for flexible thin film transistor (TFT)-based electronic circuits, three different nanomaterial-based inks (silver nanoparticles, BaTiO3 nanoparticles and single-walled carbon nanotubes (SWNTs)) were selected and optimized to enable the realization of fully printed SWNT-based TFTs (SWNT-TFTs) on 150-m-long rolls of 0.25-m-wide poly(ethylene terephthalate) (PET). SWNT-TFTs with 5 different channel lengths, namely, 30, 80, 130, 180, and 230 μm, were fabricated using a printing speed of 8 m/min. These SWNT-TFTs were characterized, and the obtained electrical parameters were related to major mechanical factors such as web tension, registration accuracy, impression roll pressure and printing speed to determine whether these mechanical factors were the sources of the observed device-to-device variations. By utilizing the electrical parameters from the SWNT-TFTs, a Monte Carlo simulation for a 1-bit adder circuit, as a reference, was conducted to demonstrate that functional circuits with reasonable complexity can indeed be manufactured using R2R gravure printing. The simulation results suggest that circuits with complexity, similar to the full adder circuit, can be printed with a 76% circuit yield if threshold voltage (Vth) variations of less than 30% can be maintained.

  14. Thinning and rupture of a thin liquid film on a heated surface

    Energy Technology Data Exchange (ETDEWEB)

    Bankoff, S.G.; Davis, S.H.

    1992-08-05

    Results on the dynamics and stability of thin films are summarized on the following topics: forced dryout, film instabilities on a horizontal plane and on inclined planes, instrumentation, coating flows, and droplet spreading. (DLC)

  15. The NO2 sensing ITO thin films prepared by ultrasonic spray pyrolysis

    OpenAIRE

    Jianzhong Gu; Minghua Lu; Zheng Qin; Minghong Wu; Zheng Jiao

    2003-01-01

    In this paper ITO thin films were deposited on alumina substrates by ultrasonic spray pyrolysis. The NO2 sensing properties of ITO thin films were investigated. The results show ITO thin films have good sensitivity to nitrogen dioxide.

  16. Controlled nanostructuration of polycrystalline tungsten thin films

    Energy Technology Data Exchange (ETDEWEB)

    Girault, B. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), LUNAM Universite, Universite de Nantes, Centrale Nantes, CRTT, 37 Bd de l' Universite, BP 406, 44602 Saint-Nazaire Cedex (France); Eyidi, D.; Goudeau, P.; Guerin, P.; Bourhis, E. Le; Renault, P.-O. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Sauvage, T. [CEMHTI/CNRS (UPR 3079 CNRS), Universite d' Orleans, 3A rue de la Ferollerie, 45071 Orleans Cedex 2 (France)

    2013-05-07

    Nanostructured tungsten thin films have been obtained by ion beam sputtering technique stopping periodically the growing. The total thickness was maintained constant while nanostructure control was obtained using different stopping periods in order to induce film stratification. The effect of tungsten sublayers' thicknesses on film composition, residual stresses, and crystalline texture evolution has been established. Our study reveals that tungsten crystallizes in both stable {alpha}- and metastable {beta}-phases and that volume proportions evolve with deposited sublayers' thicknesses. {alpha}-W phase shows original fiber texture development with two major preferential crystallographic orientations, namely, {alpha}-W<110> and unexpectedly {alpha}-W<111> texture components. The partial pressure of oxygen and presence of carbon have been identified as critical parameters for the growth of metastable {beta}-W phase. Moreover, the texture development of {alpha}-W phase with two texture components is shown to be the result of a competition between crystallographic planes energy minimization and crystallographic orientation channeling effect maximization. Controlled grain size can be achieved for the {alpha}-W phase structure over 3 nm stratification step. Below, the {beta}-W phase structure becomes predominant.

  17. Vertically aligned biaxially textured molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Rahul [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Riley, Michael [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lee, Sabrina [US Army Armament Research, Development and Engineering Center, Benet Labs, Watervliet, New York 12189 (United States); Lu, Toh-Ming [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2011-09-15

    Vertically aligned, biaxially textured molybdenum nanorods were deposited using dc magnetron sputtering with glancing flux incidence (alpha = 85 degrees with respect to the substrate normal) and a two-step substrate-rotation mode. These nanorods were identified with a body-centered cubic crystal structure. The formation of a vertically aligned biaxial texture with a [110] out-of-plane orientation was combined with a [-110] in-plane orientation. The kinetics of the growth process was found to be highly sensitive to an optimum rest time of 35 seconds for the two-step substrate rotation mode. At all other rest times, the nanorods possessed two separate biaxial textures each tilted toward one flux direction. While the in-plane texture for the vertical nanorods maintains maximum flux capture area, inclined Mo nanorods deposited at alpha = 85 degrees without substrate rotation display a [-1-1-4] in-plane texture that does not comply with the maximum flux capture area argument. Finally, an in situ capping film was deposited with normal flux incidence over the biaxially textured vertical nanorods resulting in a thin film over the porous nanorods. This capping film possessed the same biaxial texture as the nanorods and could serve as an effective substrate for the epitaxial growth of other functional materials.

  18. Use of thin films in high-temperature superconducting bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.; Cansiz, A.

    1999-09-30

    In a PM/HTS bearing, locating a thin-film HTS above a bulk HTS was expected to maintain the large levitation force provided by the bulk with a lower rotational drag provided by the very high current density of the film. For low drag to be achieved, the thin film must shield the bulk from inhomogeneous magnetic fields. Measurement of rotational drag of a PM/HTS bearing that used a combination of bulk and film HTS showed that the thin film is not effective in reducing the rotational drag. Subsequent experiments, in which an AC coil was placed above the thin-film HTS and the magnetic field on the other side of the film was measured, showed that the thin film provides good shielding when the coil axis is perpendicular to the film surface but poor shielding when the coil axis is parallel to the surface. This is consistent with the lack of reduction in rotational drag being due to a horizontal magnetic moment of the permanent magnet. The poor shielding with the coil axis parallel to the film surface is attributed to the aspect ratio of the film and the three-dimensional nature of the current flow in the film for this coil orientation.

  19. Structural and Optical Properties of Nanoscale Galinobisuitite Thin Films

    Directory of Open Access Journals (Sweden)

    Omar H. Abd-Elkader

    2014-01-01

    Full Text Available Galinobisuitite thin films of (Bi2S3(PbS were prepared using the chemical bath deposition technique (CBD. Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA complex of Bi3+ and Pb2+ to react with S2− ions, which are released slowly by the dissociation of the thiourea (TU solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM, transmission electron microscopes (TEM and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements.

  20. Some Aspects of the Failure Mechanisms in BaTiO3-Based Multilayer Ceramic Capacitors

    Science.gov (United States)

    Liu, David Donhang; Sampson, Michael J.

    2012-01-01

    The objective of this presentation is to gain insight into possible failure mechanisms in BaTiO3-based ceramic capacitors that may be associated with the reliability degradation that accompanies a reduction in dielectric thickness, as reported by Intel Corporation in 2010. The volumetric efficiency (microF/cm3) of a multilayer ceramic capacitor (MLCC) has been shown to not increase limitlessly due to the grain size effect on the dielectric constant of ferroelectric ceramic BaTiO3 material. The reliability of an MLCC has been discussed with respect to its structure. The MLCCs with higher numbers of dielectric layers will pose more challenges for the reliability of dielectric material, which is the case for most base-metal-electrode (BME) capacitors. A number of MLCCs manufactured using both precious-metal-electrode (PME) and BME technology, with 25 V rating and various chip sizes and capacitances, were tested at accelerated stress levels. Most of these MLCCs had a failure behavior with two mixed failure modes: the well-known rapid dielectric wearout, and so-called 'early failures." The two failure modes can be distinguished when the testing data were presented and normalized at use-level using a 2-parameter Weibull plot. The early failures had a slope parameter of Beta >1, indicating that the early failures are not infant mortalities. Early failures are triggered due to external electrical overstress and become dominant as dielectric layer thickness decreases, accompanied by a dramatic reduction in reliability. This indicates that early failures are the main cause of the reliability degradation in MLCCs as dielectric layer thickness decreases. All of the early failures are characterized by an avalanche-like breakdown leakage current. The failures have been attributed to the extrinsic minor construction defects introduced during fabrication of the capacitors. A reliability model including dielectric thickness and extrinsic defect feature size is proposed in this presentation. The model can be used to explain the Intel-reported reliability degradation in MLCCs with respect to the reduction of dielectric thickness. It can also be used to estimate the reliability of a MLCC based on its construction and microstructure parameters such as dielectric thickness, average grain size, and number of dielectric layers. Measures for preventing early failures are also discussed in this document.

  1. Structural And Optical Properties Of VOx Thin Films

    OpenAIRE

    Schneider K.

    2015-01-01

    VOx thin films were deposited on Corning glass, fused silica and Ti foils by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. Influence of the oxygen partial pressure in the sputtering chamber on the structural and optical properties of thin films has been investigated.

  2. Optimized grid design for thin film solar panels

    NARCIS (Netherlands)

    Deelen, J. van; Klerk, L.; Barink, M.

    2014-01-01

    There is a gap in efficiency between record thin film cells and mass produced thin film solar panels. In this paper we quantify the effect of monolithic integration on power output for various configurations by modeling and present metallization as a way to improve efficiency of solar panels. Grid d

  3. Eutectic bonds on wafer scale by thin film multilayers

    Science.gov (United States)

    Christensen, Carsten; Bouwstra, Siebe

    1996-09-01

    The use of gold based thin film multilayer systems for forming eutectic bonds on wafer scale is investigated and preliminary results will be presented. On polished 4 inch wafers different multilayer systems are developed using thin film techniques and bonded afterwards under reactive atmospheres and different bonding temperatures and forces. Pull tests are performed to extract the bonding strengths.

  4. Effect of film thickness and texture morphology on the physical properties of lead sulfide thin films

    Science.gov (United States)

    Azadi Motlagh, Z.; Azim Araghi, M. E.

    2016-02-01

    Lead sulfide (PbS) thin films were prepared onto ultra-clean quartz substrate by the electron beam gun (EBG) evaporation method. The thicknesses of the thin films were 50, 100, 150 and 200 nm. They were annealed at 423 K for 2 h. Field emission scanning electron microscopy (FESEM) images of the thin films showed their texture morphology at the surface of the quartz substrate. X-ray diffraction (XRD) patterns of the thin films showed that they have a cubic phase and rock-salt structure after annealing. The average crystallite size for the thin films was in the range of 32-100 nm. Optical measurements confirmed that crystalline thin films have a direct band gap that increases by decreasing the film thickness. This blue shift of the band gap of thin films compared to the bulk structure can be attributed to the quantum confinement effects in the nanoparticles. A decrease in conductivity by increasing the temperature confirmed the positive temperature coefficient of resistance in the thin films that showed the dominant conduction mechanism is via a band-like transition. The density of localized states at the Fermi level increases by increasing the film thickness. Current-voltage behavior of the thin films showed an increase in both dark current and photocurrent by increasing the crystallite size which is discussed, based on the presence of trap states and barriers in nanostructures.

  5. Effect of film thickness and texture morphology on the physical properties of lead sulfide thin films

    International Nuclear Information System (INIS)

    Lead sulfide (PbS) thin films were prepared onto ultra-clean quartz substrate by the electron beam gun (EBG) evaporation method. The thicknesses of the thin films were 50, 100, 150 and 200 nm. They were annealed at 423 K for 2 h. Field emission scanning electron microscopy (FESEM) images of the thin films showed their texture morphology at the surface of the quartz substrate. X-ray diffraction (XRD) patterns of the thin films showed that they have a cubic phase and rock-salt structure after annealing. The average crystallite size for the thin films was in the range of 32–100 nm. Optical measurements confirmed that crystalline thin films have a direct band gap that increases by decreasing the film thickness. This blue shift of the band gap of thin films compared to the bulk structure can be attributed to the quantum confinement effects in the nanoparticles. A decrease in conductivity by increasing the temperature confirmed the positive temperature coefficient of resistance in the thin films that showed the dominant conduction mechanism is via a band-like transition. The density of localized states at the Fermi level increases by increasing the film thickness. Current–voltage behavior of the thin films showed an increase in both dark current and photocurrent by increasing the crystallite size which is discussed, based on the presence of trap states and barriers in nanostructures. (paper)

  6. Infrared analysis of thin films amorphous, hydrogenated carbon on silicon

    CERN Document Server

    Jacob, W; Schwarz-Selinger, T

    2000-01-01

    The infrared analysis of thin films on a thick substrate is discussed using the example of plasma-deposited, amorphous, hydrogenated carbon layers (a-C:H) on silicon substrates. The framework for the optical analysis of thin films is presented. The main characteristic of thin film optics is the occurrence of interference effects due to the coherent superposition of light multiply reflected at the various internal and external interfaces of the optical system. These interference effects lead to a sinusoidal variation of the transmitted and reflected intensity. As a consequence, the Lambert-Beer law is not applicable for the determination of the absorption coefficient of thin films. Furthermore, observable changes of the transmission and reflection spectra occur in the vicinity of strong absorption bands due to the Kramers-Kronig relation. For a sound data evaluation these effects have to be included in the analysis. To be able to extract the full information contained in a measured optical thin film spectrum, ...

  7. Nanotwin hardening in a cubic chromium oxide thin film

    Directory of Open Access Journals (Sweden)

    Kazuma Suzuki

    2015-09-01

    Full Text Available NaCl-type (B1 chromium oxide (CrO has been expected to have a high hardness value and does not exist as an equilibrium phase. We report a B1-based Cr0.67O thin film with a thickness of 144 nm prepared by pulsed laser deposition as an epitaxial thin film on a MgO single crystal. The thin film contained a number of stacking faults and had a nanotwinned structure composed of B1 with disordered vacancies and corundum structures. The Cr0.67O thin film had a high indentation hardness value of 44 GPa, making it the hardest oxide thin film reported to date.

  8. Nanocoatings and ultra-thin films technologies and applications

    CERN Document Server

    Tiginyanu, Ion

    2011-01-01

    Gives a comprehensive account of the developments of nanocoatings and ultra-thin films. This book covers the fundamentals, processes of deposition and characterisation of nanocoatings, as well as the applications. It is suitable for the glass and glazing, automotive, electronics, aerospace, construction and biomedical industries in particular.$bCoatings are used for a wide range of applications, from anti-fogging coatings for glass through to corrosion control in the aerospace and automotive industries. Nanocoatings and ultra-thin films provides an up-to-date review of the fundamentals, processes of deposition, characterisation and applications of nanocoatings. Part one covers technologies used in the creation and analysis of thin films, including chapters on current and advanced coating technologies in industry, nanostructured thin films from amphiphilic molecules, chemical and physical vapour deposition methods and methods for analysing nanocoatings and ultra-thin films. Part two focuses on the applications...

  9. Physical properties in thin films of iron oxides.

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Girata, D.; Morales, A. L.; Hoffmann, A.; Materials Science Division; Univ. de Antioquia

    2008-01-01

    We have grown hematite ({alpha}-Fe{sub 2}O{sub 3}) thin films on stainless steel substrates and magnetite (Fe{sub 3}O{sub 4}) thin films on (0 0 1)-Si single crystal substrates by a RF magnetron sputtering process. {alpha}-Fe{sub 2}O{sub 3} thin films were grown in an Ar atmosphere at substrate temperatures around 400 C, and Fe{sub 3}O{sub 4} thin films in an Ar/O{sub 2} reactive atmosphere at substrate temperatures around 500 C. Conversion electron Moessbauer (CEM) spectra of {alpha}-Fe{sub 2}O{sub 3} thin films exhibit values for hyperfine parameter characteristic of the hematite stoichiometric phase in the weak ferromagnetic state [R.E. Vandenberghe, in: Moessbauer Spectroscopy and Applications in Geology, University Gent, Belgium, 1990. [1

  10. Thin films and coatings toughening and toughness characterization

    CERN Document Server

    Zhang, Sam

    2015-01-01

    Thin Films and Coatings: Toughening and Toughness Characterization captures the latest developments in the toughening of hard coatings and in the measurement of the toughness of thin films and coatings. Featuring chapters contributed by experts from Australia, China, Czech Republic, Poland, Singapore, Spain, and the United Kingdom, this first-of-its-kind book:Presents the current status of hard-yet-tough ceramic coatingsReviews various toughness evaluation methods for films and hard coatingsExplores the toughness and toughening mechanisms of porous thin films and laser-treated surfacesExamines

  11. Preface: Advanced Thin Film Developments and Nano Structures

    Institute of Scientific and Technical Information of China (English)

    Ray Y.Lin

    2005-01-01

    @@ In this special issue, we invited a few leading materials researchers to present topics in thin films, coatings, and nano structures. Readers will find most recent developments in topics, including recent advances in hard, tough, and low friction nanocomposite coatings; thin films for coating nanomaterials; electroless plating of silver thin films on porous Al2O3 substrate; CrN/Nano Cr interlayer coatings; nano-structured carbide derived carbon (CDC) films and their tribology; predicting interdiffusion in high-temperature coatings; gallium-catalyzed silica nanowire growth; and corrosion protection properties of organofunctional silanes. Authors are from both national laboratories and academia.

  12. Peculiarities of spin reorientation in a thin YIG film

    Energy Technology Data Exchange (ETDEWEB)

    Bazaliy, Ya.B.; Tsymbal, L.T.; Linnik, A.I.; Dan' shin, N.K.; Izotov, A.I.; Wigen, P.E

    2003-05-01

    The issue of magnetic orientation transitions in thin films combines interesting physics and importance for applications. We study the magnetic transition and phase diagram of a 0.1 {mu}m thick (YLaGd){sub 3}(FeGa){sub 5}O{sub 12} films grown on GGG substrate by liquid phase epitaxy. Observed transitions are compared with those in BiGa:TmIG thin films, studied in previous work by one of the authors. A general picture of orientation transitions in thin films of substituted YIG is discussed.

  13. Peculiarities of spin reorientation in a thin YIG film.

    Energy Technology Data Exchange (ETDEWEB)

    Bazaliy, Ya. B.; Tsymbal, L. T.; Linnik, A. I.; Dan' shin, N. K.; Izotov, A. I.; Wigen, P. E.

    2002-06-28

    The issue of magnetic orientation transitions in thin films combines interesting physics and importance for applications. We study the magnetic transition and phase diagram of a 0.1{micro}m thick (YLaGd){sub 3}(FeGa){sub 5}O{sub 12} films grown on GGG substrate by liquid phase epitaxy. Observed transitions are compared with those in BiGa:TmIG thin films, studied in previous work by one of the authors. A general picture of orientation transitions in thin films of substituted YIG is discussed.

  14. Electrochemical Intercalation of Sodium into Silicon Thin Film

    Institute of Scientific and Technical Information of China (English)

    Dong-Yeon Kim; Hyo-Jun Ahn; Gyu-Bong Cho; Jong-Seon Kim; Ho-Suk Ryu; Ki-Won Kim; Jou-Hyeon Ahn; Won-Cheol Shin

    2008-01-01

    In order to investigate the possibility of Si thin film as an anode for Na battery, we studied the electrochemical intercalation of sodium into the Si film. Amorphous Si thin film electrode was prepared using DC magnetron sputtering. Sodium ion could intercalate into Si thin film upto Na0.52Si, i.e. 530mAh · g-1-Si. The first discharge capacity was 80mAh.·g-1-Si, which meant reversible amount of sodium intercalation. The discharge capacity slightly decreased to 70mAh · g-1-Si after 10 cycles.

  15. LaAlO3/BaTiO3超晶格薄膜界面结构分析%Analysis of Microstructures of LaAlO3/BaTiO3 Superlattice

    Institute of Scientific and Technical Information of China (English)

    郝兰众; 李燕; 邓宏; 刘云杰; 姬洪

    2005-01-01

    通过研究发现,利用激光分子束外延技术生长的LaAlO3/BaTiO3超晶格薄膜具有良好的电学性能,其剩余极化可达到25μc/cm2.性能决定于结构,因此本文分析研究了LaAlO3/BaTiO3超晶格薄膜的界面结构.首先通过高能电子衍射技术在薄膜生长过程中对各层的生长及界面状况进行观测,再通过小角X射线衍射曲线及其计算机拟合曲线进一步确定超晶格薄膜的界面及结构参数,如界面的粗糙度、单层厚度等.通过研究发现,由于晶格之间的差异,LaAlO3/BaTiO3超晶格薄膜中LaAlO3和BaTiO3层的生长过程及微结构存在着一定的差异.

  16. Thin Films for Advanced Glazing Applications

    Directory of Open Access Journals (Sweden)

    Ann-Louise Anderson

    2016-09-01

    Full Text Available Functional thin films provide many opportunities for advanced glazing systems. This can be achieved by adding additional functionalities such as self-cleaning or power generation, or alternately by providing energy demand reduction through the management or modulation of solar heat gain or blackbody radiation using spectrally selective films or chromogenic materials. Self-cleaning materials have been generating increasing interest for the past two decades. They may be based on hydrophobic or hydrophilic systems and are often inspired by nature, for example hydrophobic systems based on mimicking the lotus leaf. These materials help to maintain the aesthetic properties of the building, help to maintain a comfortable working environment and in the case of photocatalytic materials, may provide external pollutant remediation. Power generation through window coatings is a relatively new idea and is based around the use of semi-transparent solar cells as windows. In this fashion, energy can be generated whilst also absorbing some solar heat. There is also the possibility, in the case of dye sensitized solar cells, to tune the coloration of the window that provides unheralded external aesthetic possibilities. Materials and coatings for energy demand reduction is highly desirable in an increasingly energy intensive world. We discuss new developments with low emissivity coatings as the need to replace scarce indium becomes more apparent. We go on to discuss thermochromic systems based on vanadium dioxide films. Such systems are dynamic in nature and present a more sophisticated and potentially more beneficial approach to reducing energy demand than static systems such as low emissivity and solar control coatings. The ability to be able to tune some of the material parameters in order to optimize the film performance for a given climate provides exciting opportunities for future technologies. In this article, we review recent progress and challenges in

  17. A versatile platform for magnetostriction measurements in thin films

    Science.gov (United States)

    Pernpeintner, M.; Holländer, R. B.; Seitner, M. J.; Weig, E. M.; Gross, R.; Goennenwein, S. T. B.; Huebl, H.

    2016-03-01

    We present a versatile nanomechanical sensing platform for the investigation of magnetostriction in thin films. It is based on a doubly clamped silicon nitride nanobeam resonator covered with a thin magnetostrictive film. Changing the magnetization direction within the film plane by an applied magnetic field generates a magnetoelastic stress and thus changes the resonance frequency of the nanobeam. A measurement of the resulting resonance frequency shift, e.g., by optical interferometry, allows to quantitatively determine the magnetostriction constants of the thin film. In a proof-of-principle experiment, we determine the magnetostriction constants of a 10 nm thick polycrystalline cobalt film, showing very good agreement with literature values. The presented technique aims, in particular, for the precise measurement of magnetostriction in a variety of (conducting and insulating) thin films, which can be deposited by, e.g., electron beam deposition, thermal evaporation, or sputtering.

  18. The Structure and Stability of Molybdenum Ditelluride Thin Films

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Molybdenum-tellurium alloy thin films were fabricated by electron beam evaporation and the films were annealed in different conditions in N2 ambient. The hexagonal molybdenum ditelluride thin films with well crystallization annealed at 470°C or higher were obtained by solid state reactions. Thermal stability measurements indicate the formation of MoTe2 took place at about 350°C, and a subtle weight-loss was in the range between 30°C and 500°C. The evolution of the chemistry for Mo-Te thin films was performed to investigate the growth of the MoTe2 thin films free of any secondary phase. And the effect of other postdeposition treatments on the film characteristics was also investigated.

  19. Mechanism and characters of thin film lubrication at nanometer scale

    Institute of Scientific and Technical Information of China (English)

    雒建斌; 温诗铸

    1996-01-01

    Thin film lubrication is a transition region between elastohydrodynamic lubrication and boundary lubrication, A technique of relative optical interference intensity with the resolution of 0.5 nm in the vertical direction and 1.5 nm in the horizontal direction is used in a pure rolling process to measure the film thickness with different lubricants, speeds, loads and substrate surface energy. Experimental data show that the characteristics of thin film lubrication are different from those of elastohydrodynamic lubrication and boundary lubrication. As the rolling speed decreases, a critical film thickness can be found to distinguish thin film lubrication from elastohydrodynamic lubrication. Such thickness is related to the substrate surface energy, atmospheric viscosity of lubricant, etc. A physical model of thin film lubrication with the fluid layer, the ordered liquid layer and the adsorbed layer is proposed and the functions of these different layers are discussed.

  20. Doping Effects of Rare Earth on Dielectric Properties of Fine-Grained BaTiO3-Based Ceramics

    Institute of Scientific and Technical Information of China (English)

    李玲霞; 郭炜; 吴霞宛; 王洪儒; 张志萍

    2003-01-01

    The doping effects of rare earth oxides Ho2O3 and Er2O3 on dielectric properties of BaTiO3-based ceramics were studied. After adding rare earth elements, grain growth in this system was inhibited and the grain size was reduce devidently which realized the fine-grained effect. In this system, the trivalent oxides Ho2O3 and Er2O3 were added to BaTiO3 ceramics. The rare earth oxides do not enter into inner lattice totally to replace A or B sites. Some of additives can improve dielectric strength by forming nonferroelectric phases, and the rest maintained at grain boundaries controls overgrowth of grains. The dielectric constant at room temperature is increased up to 3000 and the curve of TCC becomes flat. Meanwhile, the dielectric strength Eb becomes higher.

  1. High calcination of ferroelectric BaTiO3 doped Fe nanoceramics prepared by a solid-state sintering method

    Science.gov (United States)

    Samuvel, K.; Ramachandran, K.

    2015-07-01

    This study examined the effects of the combination of starting materials on the properties of solid-state reacted BaTiO3 using two different types of BaCO3 and TiO2. In addition, the effect of mechanochemical activation by high energy milling and the Ba/Ti molar ratio on the reaction temperature, particle size and tetragonality were investigated. The TiO2 phase and size plays a major role in increasing the reaction temperature and particle size. With the optimum selection of starting materials and processing conditions, BaTiO3 with a particle size Cole-Cole plots in complex impedance and modulus formalism. Modulus formalism has identified the effects of both grain and grain boundary microstructure on the dielectric properties, particularly in solid state routed samples.

  2. Giant room-temperature barocaloric effect and pressure-mediated electrocaloric effect in BaTiO3 single crystal

    International Nuclear Information System (INIS)

    Barocaloric effect in BaTiO3 single crystal is studied by a thermodynamic phenomenological model. It is demonstrated that a giant barocaloric effect can be achieved near room temperature with an adiabatic temperature change of more than 3 K and a temperature span about 50 K. As expected, the electrocaloric peak can be shifted towards room temperature by pressure. However, a slight reduction of the electrocaloric peak is found in contrast to relaxor ferroelectrics and LiNbO3. We believe that our findings could open a potential route by combining the barocaloric effect and pressure-mediated electrocaloric effect in BaTiO3 single crystal for cooling devices

  3. Slippage and Nanorheology of Thin Liquid Polymer Films

    OpenAIRE

    Bäumchen, Oliver; Fetzer, Renate; Klos, Mischa; Lessel, Matthias; Marquant, Ludovic; Hähl, Hendrik; Jacobs, Karin

    2012-01-01

    Thin liquid films on surfaces are part of our everyday life, they serve e.g. as coatings or lubricants. The stability of a thin layer is governed by interfacial forces, described by the effective interface potential, and has been subject of many studies in the last decades. In recent years, the dynamics of thin liquid films came into focus since results on the reduction of the glass transition temperature raised new questions on the behavior of especially polymeric liquids in confined geometr...

  4. The Potentiostatic Electrodeposition of Indium doped Aluminium Selenide Thin Films

    Directory of Open Access Journals (Sweden)

    R.K. Pathak and Sipi Mohan

    2013-12-01

    Full Text Available The In containing AlSe thin films were electrosynthesized by electrochemical co-deposition technique. The morphological properties of thin films were studied through the Scanning Electron Micrograph (SEM while the structural features through X-Ray Diffraction technique (XRD. The deposition current along with the film thickness values, the charge carrier density, flat band potential, corrosion characteristics i.e., corrosion current, corrosion potential and corrosion rate were calculated.

  5. Pulsed laser deposition and characterisation of thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Morone, A. [CNR, zona industriale di Tito Scalo, Potenza (Italy). Istituto per i Materiali Speciali

    1996-09-01

    Same concepts on pulsed laser deposition of thin films will be discussed and same examples of high transition temperature (HTc) BiSrCaCuO (BISCO) and low transition temperature NbN/MgO/NbN multilayers will be presented. X-ray and others characterizations of these films will be reported and discussed. Electrical properties of superconducting thin films will be realized as a function of structural and morphological aspect.

  6. Production of selective membranes using plasma deposited nanochanneled thin films

    OpenAIRE

    Rodrigo Amorim Motta Carvalho; Alexsander Tressino Carvalho; Maria Lúcia Pereira da Silva; Nicole Raymond Demarquette

    2006-01-01

    The hydrolization of thin films obtained by tetraethoxysilane plasma polymerization results in the formation of a nanochanneled silicone like structure that could be useful for the production of selective membranes. Therefore, the aim of this work is to test the permeation properties of hydrolyzed thin films. The films were tested for: 1) permeation of polar organic compounds and/or water in gaseous phase and 2) permeation of salt in liquid phase. The efficiency of permeation was tested using...

  7. Thin film adhesion by nanoindentation-induced superlayers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gerberich, William W.; Volinsky, A.A.

    2001-06-01

    This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.

  8. On the nature of shear thinning in nanoscopically confined films

    OpenAIRE

    Manias, E; Bitsanis, I.; Hadziioannou, G.; Brinke, G. ten

    1996-01-01

    Non-Equilibrium Molecular Dynamics (NEMD) computer simulations were employed to study films in nanometer confinements under shear. Focusing on the response of the viscosity, we found that nearly all the shear thinning takes place inside the solid-oligomer interface and that the adsorbed layers are more viscous than the middle part of the films. Moreover, the shear thinning inside the interfacial area is determined by the wall affinity and is largely insensitive to changes of the film thicknes...

  9. On Ginzburg-Landau Vortices of Superconducting Thin Films

    Institute of Scientific and Technical Information of China (English)

    Shi Jin DING; Qiang DU

    2006-01-01

    In this paper, we discuss the vortex structure of the superconducting thin films placed in a magnetic field. We show that the global minimizer of the functional modelling the superconducting thin films has a bounded number of vortices when the applied magnetic field hex < Hc1 + K log |log ε|where Hc1 is the lower critical field of the film obtained by Ding and Du in SIAM J. Math. Anal.,2002. The locations of the vortices are also given.

  10. Low-frequency dielectric spectroscopy of BaTiO3:Ce3+ ceramics

    Science.gov (United States)

    Berbecaru, Ciceron

    2015-10-01

    Dielectric spectroscopy of BaTiO3 (BT) doped with Ce3+ (BT:Ce3+) ceramics was performed at extended temperatures and in the low-frequency ranges. BT:Ce3+ displays decreasing values of all phase transition temperatures with increasing Ce3+ content. Permittivity versus temperature plots showed decreasing values with increasing frequency with low dispersion and shifting values of the Curie temperatures (Tc) towards high frequencies. Comparable values of losses for BT and BT:Ce3+ ceramics suggest good charge compensation. At low frequencies and higher temperatures, thermally activated mechanisms of conduction increase the loss values. With increasing frequency, the BT:Ce3+ system displays increased and shifted loss peaks up to Tc and decreasing values above Tc. The characteristic exponent of the modified Curie-Weiss law is higher than one. These figures suggest a relaxor-like behaviour of BT:Ce3+ ceramics for low Ce3+ content. Phase diagrams of BT:Ce3+ ceramics show a strong decrease of Tc for low Ce3+ content.

  11. Spatial subharmonic generation of orthogonally polarized light waves in BaTiO(3) by phase-matched nonlinear mixing.

    Science.gov (United States)

    Novikov, A; Odoulov, S; Jungen, R; Tschudi, T

    1991-12-15

    The development of a spatial subharmonic, i.e., of a light wave propagating at the bisector of two pump waves, with orthogonal polarizations incident upon a BaTiO(3) crystal in a plane normal to the optical axis is observed and studied. Parametric amplification of a seed wave meeting the phase-matching condition in the presence of two pump waves is shown to be the main reason for subharmonic generation in this crystal.

  12. Total energy calculation of perovskite, BaTiO3, by self-consistent tight binding method

    Indian Academy of Sciences (India)

    B T Cong; P N A Huy; P K Schelling; J W Halley

    2003-01-01

    We present results of numerical computation on some characteristics of BaTiO3 such as total energy, lattice constant, density of states, band structure etc using self-consistent tight binding method. Besides strong Ti–O bond between 3 on titanium and 2 orbital on oxygen states, we also include weak hybridization between the Ba 6 and O 2 states. The results are compared with those of other more sophisticated methods.

  13. Amperometric Noise at Thin Film Band Electrodes

    DEFF Research Database (Denmark)

    Larsen, Simon T.; Heien, Michael L.; Taboryski, Rafael

    2012-01-01

    polymers and measured the current noise in physiological buffer solution for a wide range of different electrode areas. The noise measurements could be modeled by an analytical expression, representing the electrochemical cell as a resistor and capacitor in series. The studies revealed three domains......; for electrodes with low capacitance, the amplifier noise dominated, for electrodes with large capacitances, the noise from the resistance of the electrochemical cell was dominant, while in the intermediate region, the current noise scaled with electrode capacitance. The experimental results and the model......Background current noise is often a significant limitation when using constant-potential amperometry for biosensor application such as amperometric recordings of transmitter release from single cells through exocytosis. In this paper, we fabricated thin-film electrodes of gold and conductive...

  14. Electrochromism: from oxide thin films to devices

    Science.gov (United States)

    Rougier, A.; Danine, A.; Faure, C.; Buffière, S.

    2014-03-01

    In respect of their adaptability and performance, electrochromic devices, ECDs, which are able to change their optical properties under an applied voltage, have received significant attention. Target applications are multifold both in the visible region (automotive sunroofs, smart windows, ophthalmic lenses, and domestic appliances (oven, fridge…)) and in the infrared region (Satellites Thermal Control, IR furtivity). In our group, focusing on oxide thin films grown preferentially at room temperature, optimization of ECDs performances have been achieved by tuning the microstructure, the stoichiometry and the cationic composition of the various layers. Herein, our approach for optimized ECDs is illustrated through the example of WO3 electrochromic layer in the visible and in the IR domain as well as ZnO based transparent conducting oxide layer. Targeting the field of printed electronics, simplification of the device architecture for low power ECDs is also reported.

  15. Transport measurements in overdoped YBCO thin films

    International Nuclear Information System (INIS)

    Temperature dependence of Hall constant RH and longitudinal resistivity ρxx have been measured in Ca-doped YBCO thin films with varying oxygen contents, with emphasis on the overdoped regime. RH vs. T data present a peak near Tc whose height reduces with doping and disappears at optimal doping. Unexpectedly, the peak reappears above optimal doping with a height that increases with doping. A similar behavior was observed in the parameters that fit cot(θH) vs. T to a parabola. They decrease smoothly with increasing doping in the underdoped region and present a peculiar peak in the overdoped region. This behavior might indicate the crossover to a new regime of transport properties in strongly overdoped HTSC. We discuss the possible origin and implications of these results

  16. Surfactant Spreading on Thin Viscous Fluid Films

    Science.gov (United States)

    Bonilla, Caitlyn; Leslie, Nathaniel; Liu, Jeanette; Sinclair, Dina; Levy, Rachel

    2014-11-01

    We examine the spreading of insoluble lipids on a viscous Newtonian thin fluid film. This spreading can be modeled as two coupled nonlinear fourth-order partial differential equations, though inconsistencies between the timescale of experiments and simulations have been reported in recent research. In simulations, we replace traditional models for the equation of state relating surfactant concentration to surface tension with an empirical equation of state. Isotherms collected via a Langmuir-Pockels scale provide data for the equation of state. We compare the timescale of simulation results to measurements of the fluorescently tagged lipid (NBD-PC) spreading as well as the height profile, captured with laser profilometry. Research supported by NSF-DMS-FRG 9068154, RCSA-CCS-19788, HHMI.

  17. Photoluminescence studies in epitaxial CZTSe thin films

    Science.gov (United States)

    Sendler, Jan; Thevenin, Maxime; Werner, Florian; Redinger, Alex; Li, Shuyi; Hägglund, Carl; Platzer-Björkman, Charlotte; Siebentritt, Susanne

    2016-09-01

    Epitaxial Cu 2 ZnSnSe 4 (CZTSe) thin films were grown by molecular beam epitaxy on GaAs(001) using two different growth processes, one containing an in-situ annealing stage as used for solar cell absorbers and one for which this step was omitted. Photoluminescences (PL) measurements carried out on these samples show no dependence of the emission shape on the excitation intensity at different temperatures ranging from 4 K to 300 K . To describe the PL measurements, we employ a model with fluctuating band edges in which the density of states of the resulting tail states does not seem to depend on the excited charge carrier density. In this interpretation, the PL measurements show that the annealing stage removes a defect level, which is present in the samples without this annealing.

  18. Structure and Microstructure of Ni-Mn-Ga thin films

    OpenAIRE

    A. Annadurai

    2013-01-01

    Ni-Mn-Ga thin films were dc magnetron sputter deposited onto well cleaned substrates of si(100) and glass in high pure argon atmosphere of pressure of 0.01 mbar using NiMnGa alloy targets prepared in ourlaboratory by vacuum induction melting technique. Pristine thin films were investigated. Crystal structure of the films was studied using x-ray diffraction (XRD) technique. Microstructure of the films was investigated using scanning electron microscope (SEM). XRD reveals that the films on glas...

  19. Fluorine doped vanadium dioxide thin films for smart windows

    Energy Technology Data Exchange (ETDEWEB)

    Kiri, Pragna [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Warwick, Michael E.A. [UCL Energy Institute, Central House, 14 Upper Woburn Place, London, WC1H 0HY (United Kingdom); Ridley, Ian [Bartlett School of Graduate Studies, University College London, Wates House, 22 Gordon Street, WC1H 0QB, London (United Kingdom); Binions, Russell, E-mail: r.binions@ucl.ac.uk [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom)

    2011-12-01

    Thermochromic fluorine doped thin films of vanadium dioxide were deposited from the aerosol assisted chemical vapour deposition reaction of vanadyl acetylacetonate, ethanol and trifluoroacetic acid on glass substrates. The films were characterised with scanning electron microscopy, variable temperature Raman spectroscopy and variable temperature UV/Vis spectroscopy. The incorporation of fluorine in the films led to an increase in the visible transmittance of the films whilst retaining the thermochromic properties. This approach shows promise for improving the aesthetic properties of vanadium dioxide thin films.

  20. Structural, electrical and thermoelectrical analysis of nickel sulphide thin films

    Science.gov (United States)

    Chate, P. A.; Sathe, D. J.

    2016-06-01

    A dip method is employed for the deposition of NiS2 thin film at room temperature. Nickel sulphate, succinic acid and thiourea were used as the source materials. The X-ray diffraction analysis shows that the film samples are cubic phase. The specific electrical conductivity of the film was found to be 3.16 × 10-6 (Ω cm)-1. The films show high absorption, and band gap energy value was found to be 1.37 eV. The temperature dependence of an electrical conductivity, thermoelectrical power, carrier density and carrier mobility for NiS2 thin films has been examined.

  1. Determination of magnetic properties of multilayer metallic thin films

    CERN Document Server

    Birlikseven, C

    2000-01-01

    and magnetization measurements were taken. In recent year, Giant Magnetoresistance Effect has been attracting an increasingly high interest. High sensitivity magnetic field detectors and high sensitivity read heads of magnetic media can be named as important applications of these films. In this work, magnetic and electrical properties of single layer and thin films were investigated. Multilayer thin films were supplied by Prof. Dr. A. Riza Koeymen from Texas University. Multilayer magnetic thin films are used especially for magnetic reading and magnetic writing. storing of large amount of information into small areas become possible with this technology. Single layer films were prepared using the electron beam evaporation technique. For the exact determination of film thicknesses, a careful calibration of the thicknesses was made. Magnetic properties of the multilayer films were studied using the magnetization, magnetoresistance measurements and ferromagnetic resonance technique. Besides, by fitting the exper...

  2. Thin film characterization by resonantly excited internal standing waves

    Energy Technology Data Exchange (ETDEWEB)

    Di Fonzio, S. [SINCROTRONE TRIESTE, Trieste (Italy)

    1996-09-01

    This contribution describes how a standing wave excited in a thin film can be used for the characterization of the properties of the film. By means of grazing incidence X-ray reflectometry one can deduce the total film thickness. On the other hand in making use of a strong resonance effect in the electric field intensity distribution inside a thin film on a bulk substrate one can learn more about the internal structure of the film. The profile of the internal standing wave is proven by diffraction experiments. The most appropriate non-destructive technique for the subsequent thin film characterization is angularly dependent X-ray fluorescence analysis. The existence of the resonance makes it a powerful tool for the detection of impurities and of ultra-thin maker layers, for which the position can be determined with very high precision (about 1% of the total film thickness). This latter aspect will be discussed here on samples which had a thin Ti marker layer at different positions in a carbon film. Due to the resonance enhancement it was still possible to perform these experiments with a standard laboratory x-ray tube and with standard laboratory tool for marker or impurity detection in thin films.

  3. Plasma synthesis of photocatalytic TiO x thin films

    Science.gov (United States)

    Sirghi, L.

    2016-06-01

    The development of efficient photocatalytic materials is promising technology for sustainable and green energy production, fabrication of self-cleaning, bactericidal, and super hydrophilic surfaces, CO2 photoreduction, and decomposition of toxic pollutants in air and water. Semiconductors with good photocatalytic activity have been known for four decades and they are regarded as promising candidates for these new technologies. Low-pressure discharge plasma is one of the most versatile technologies being used for the deposition of photocatalytic semiconductor thin films. This article reviews the main results obtained by the author in using low-pressure plasma for synthesis of TiO x thin films with applications in photocatalysis. Titanium dioxide thin films were obtained by radio frequency magnetron sputtering deposition, plasma enhanced chemical vapour deposition, and high power impulse magnetron sputtering deposition. The effects of the plasma deposition method, plasma parameters, film thickness and substrate on the film structure, chemical composition and photocatalytic activity are investigated. The photocatalytic activity of plasma synthesised TiO x thin films was estimated by UV light induced hydrophilicity. Measurements of photocurrent decay in TiO x thin films in vacuum and air showed that the photocatalytic activity is closely connected to the production, recombination and availability for surface reactions of photo-generated charge carriers. The photocatalytic activity of TiO x thin films was investigated at nanoscale by atomic force microscopy. Microscopic regions of different hydrophilicity on UV light irradiated films are discriminated by AFM atomic force microscopy measurements of adhesion and friction force.

  4. Laser induced vibration of a thin soap film.

    OpenAIRE

    Emile, Olivier; Emile, Janine

    2014-01-01

    We report on the vibration of a thin soap film based on the optical radiation pressure force. The modulated low power laser induces a counter gravity flow in a vertical free standing draining film. The thickness of the soap film is then higher in the upper region than in the lower region of the film. Moreover, the lifetime of the film is dramatically increased by a factor of 2. Since the laser beam only acts mechanically on the film interfaces, such a film can be implemented in an optofluidic...

  5. Nonlinear generation of vorticity in thin smectic films

    CERN Document Server

    Parfenyev, V M; Lebedev, V V

    2015-01-01

    We analyze a solenoidal motion in a vertically vibrated freely suspended thin smectic film. We demonstrate analytically that transverse oscillations of the film generate two-dimensional vortices in the plane of the film owing to hydrodynamic nonlinearity. An explicit expression for the vorticity of the in-plane film motion in terms of the film displacement is obtained. The air around the film is proven to play a crucial role, since it changes the dispersion relation of transverse oscillations and transmits viscous stresses to the film, modifying its bending motion. We propose possible experimental observations enabling to check our predictions.

  6. Magnetic behavior of La2/3Ca1/3MnO3 / BaTiO3 bilayers

    Science.gov (United States)

    Ordonez, John E.; Gomez, Maria E.; Lopera, Wilson; Marin, Lorena; Pardo, Jose A.; Morellon, Luis; Algarabel, Pedro; Prieto, Pedro

    2013-03-01

    We have grown ferroelectric BaTiO3(BTO) and ferromagnetic La2/3Ca1/3MnO3 (LCMO) onto (001) SrTiO3 and Nb:SrTiO3 by pulsed laser deposition (PLD) at pure oxygen atmosphere, and a substrate temperature of 820° C, seeking for a multiferroic behavior in this structure. From x-ray diffraction (XRD) we found lattice parameter aBTO=4.068 Å, and aLCMO=3.804 Å, for each individual layer. In the BTO/LCMO bilayer, (002)-Bragg peak for BTO maintain its position whereas (002) LCMO peak shift to lower Bragg angle indicating a strained LCMO film. Magnetization measurements reveal an increase in the Curie temperature from 170 K to 220 K for the bilayer when LCMO (t = 47 nm) is deposited on BTO (t=52 nm) film, while depositing the BTO (50 nm) above LCMO (48 nm) the Curie temperature remains at values close to that obtained for a LCMO single layer (~175 K), deposited under identical growth parameters This work has been supported by Instituto de Nanociencias de Aragón, Zaragoza, Spain, ``El Patrimonio Autónomo Fondo Nacional de Financiamiento para CT&I FJC'' COLCIENCIAS-CENM Contract RC 275-2011 and Research Project COLCIENCIAS-UNIVALLE.

  7. Two approaches for enhancing the hydrogenation properties of palladium: Metal nanoparticle and thin film over layers

    Indian Academy of Sciences (India)

    Manika Khanuja; B R Mehta; S M Shivaprasad

    2008-11-01

    In the present study, two approaches have been used for enhancing the hydrogenation properties of Pd. In the first approach, metal thin film (Cu, Ag) has been deposited over Pd and hydrogenation properties of bimetal layer Cu (thin film)/Pd(thin film) and Ag(thin film)/Pd(thin film) have been studied. In the second approach, Ag metal nanoparticles have been deposited over Pd and hydrogenation properties of Ag (nanoparticle)/Pd (thin film) have been studied and compared with Ag(thin film)/Pd(thin film) bimetal layer system. The observed hydrogen sensing response is stable and reversible over a number of hydrogen loading and deloading cycles in both bimetallic systems. Alloying between Ag and Pd is suppressed in case of Ag(nanoparticle)/Pd(thin film) bimetallic layer on annealing as compared to Ag (thin film)/Pd(thin film).

  8. Effect of SiO2 addition on the dielectric properties and microstructure of BaTiO3-based ceramics in reducing sintering

    Institute of Scientific and Technical Information of China (English)

    Ying-chieh Lee; Wei-hua Lu; Su-hei Wang; Chai-wei Lin

    2009-01-01

    The effect of SiO2 doping on the sintering behavior,microstructure,and dielectric properties of BaTiO3-based ceramics has been investigated.Silica was added to the BaTiO3-based powder prepared by the solid state method with 0.075mo1%,0.15mo1%,and 0.3mo1%,respectively.The SiO2-doped BaTiO3-based ceramic with high density and uniform grain size were obtained,which were sintered in reducing atmosphere.A scanning electron microscope,X-ray diffraction,and LCR meter were used to determine the microstructure as well as the dielectric properties.SiO2 can form a liquid phase belonging to the ternary system of BaO-TiO2-SiO2,leading to the formation of BaTiO3 ceramics with high density at a lower sintering temperature.The SiO2-doped BaTiO3-based ce-ramics can be sintered to a theoretical density higher than 95% at 1220℃ with a soaking time of 2 h.The dielectric constants of the sample with 0.15mo1% SiO2 addition sintered at 1220℃ is about 9000.Doping with a small amount of silica can improve the sinter-ing and dielectric properties of BaTiO3-based ceramics.

  9. Process optimization for the sputter deposition of molybdenum thin films as electrode for AlN thin films

    International Nuclear Information System (INIS)

    Molybdenum thin films have been deposited on Ti/(100) Si substrates by dc sputtering. For process optimization, a design of experiments method was used with three input factors (target power, substrate temperature, and process gas flow). Deposition rate, resistivity, roughness, diffraction angle, and rocking curve width were analyzed as output responses using statistical analysis method. Subsequently, a process allowing the deposition of highly crystalline, smooth, and low resistivity Mo film was selected and tested against film thickness. The as-optimized sputtered molybdenum thin film was used as seeding electrode for the growth of highly c-axis textured AlN film by dc pulsed reactive sputtering

  10. thin films grown with additional NaF layers

    Science.gov (United States)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  11. Plasma polymerised thin films for flexible electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Mohan V., E-mail: mohan.jacob@jcu.edu.au [Electronic Materials Research Lab, School of Engineering and Physical Sciences, James Cook University, Townsville 4811 (Australia); Olsen, Natalie S.; Anderson, Liam J.; Bazaka, Kateryna [Electronic Materials Research Lab, School of Engineering and Physical Sciences, James Cook University, Townsville 4811 (Australia); Shanks, Robert A. [Applied Sciences, RMIT University, GPO Box 2476V, Melbourne 3001 (Australia)

    2013-11-01

    The significant advancement and growth of organic and flexible electronic applications demand materials with enhanced properties. This paper reports the fabrication of a nonsynthetic polymer thin film using radio frequency plasma polymerisation of 3,7-dimethyl-1,6-octadien-3-ol. The fabricated optically transparent thin film exhibited refractive index of approximately 1.55 at 500 nm and rate of deposition was estimated to be 40 nm/min. The surface morphology and chemical properties of the thin films were also reported in this paper. The optical band gap of the material is around 2.8 eV. The force of adhesion and Young's modulus of the linalool polymer thin films were measured using force-displacement curves obtained from a scanning probe microscope. The friction coefficient of linalool polymer thin films was measured using the nanoscratch test. The calculated Young's modulus increased linearly with increase in input power while the friction coefficient decreased. - Highlights: • Fabrication of a novel polymer thin film from non-synthetic source • The surface, optical and chemical properties are reported. • The fabricated thin film is transparent and smooth. • An environmentally friendly material • Candidate for flexible electronics as dielectric layer or as an encapsulation layer.

  12. Thin film nitinol covered stents: design and animal testing.

    Science.gov (United States)

    Levi, Daniel S; Williams, Ryan J; Liu, Jasen; Danon, Saar; Stepan, Lenka L; Panduranga, Mohanchandra K; Fishbein, Michael C; Carman, Greg P

    2008-01-01

    Interventionalists in many specialties have the need for improved, low profile covered stents. Thin films of nitinol (<5-10 microns) could be used to improve current covered stent technology. A "hot target" sputter deposition technique was used to create thin films of nitinol for this study. Covered stents were created from commercially available balloon-inflatable and self-expanding stents. Stents were deployed in a laboratory flow loop and in four swine. Uncovered stent portions served as controls. Postmortem examinations were performed 2-6 weeks after implantation. In short-term testing, thin film nitinol covered stents deployed in the arterial circulation showed no intimal proliferation and were easily removed from the arterial wall postmortem. Scanning electron microscopy showed a thin layer of endothelial cells on the thin film, which covered the entire film by 3 weeks. By contrast, significant neointimal hyperplasia occurred on the luminal side of stents deployed in the venous circulation. Extremely low-profile covered stents can be manufactured using thin films of nitinol. Although long-term studies are needed, thin film nitinol may allow for the development of low-profile, nonthrombogenic covered stents. PMID:18496269

  13. Thin film thickness measurements using Scanning White Light Interferometry

    International Nuclear Information System (INIS)

    Scanning White Light Interferometry is a well-established technique for providing accurate surface roughness measurements and three dimensional topographical images. Here we report on the use of a variant of Scanning White Light Interferometry called coherence correlation interferometry which is now capable of providing accurate thickness measurements from transparent and semi-transparent thin films with thickness below 1 μm. This capability will have many important applications which include measurements on optical coatings, displays, semiconductor devices, transparent conducting oxides and thin film photovoltaics. In this paper we report measurements of thin film thickness made using coherence correlation interferometry on a variety of materials including metal-oxides (Nb2O5 and ZrO2), a metal-nitride (SiNx:H), a carbon-nitride (SiCxNy:H) and indium tin oxide, a transparent conducting oxide. The measurements are compared with those obtained using spectroscopic ellipsometry and in all cases excellent correlation is obtained between the techniques. A key advantage of this capability is the combination of thin film thickness and surface roughness and other three-dimensional metrology measurements from the same sample area. - Highlights: • Capability to make thin film measurements with sub-nanometre accuracy • Measurements of thin film thickness made on metal-oxides, nitrides and carbon-nitrides • Excellent correlation with thickness measurements using spectroscopic ellipsometry • Thin film measurement and nanometrology from the same sample area

  14. Electron field emission from amorphous semiconductor thin films

    International Nuclear Information System (INIS)

    The flat panel display market requires new and improved technologies in order to keep up with the requirements of modem lifestyles. Electron field emission from thin film amorphous semiconductors is potentially such a technology. For this technology to become viable, improvements in the field emitting properties of these materials must be achieved. To this end, it is important that a better understanding of the emission mechanisms responsible is attained. Amorphous carbon thin films, amorphous silicon thin films and other materials have been deposited, in-house and externally. These materials have been characterised using ellipsometry, profilometry, optical absorption, scanning electron microscopy, atomic force microscopy, electron paramagnetic resonance and Rutherford backscattering spectroscopy. An experimental system for evaluating the electron field emitting performance of thin films has been developed. In the process of developing thin film cathodes in this study, it has been possible to add a new and potentially more useful semiconductor, namely amorphous silicon, to the family of cold cathode emitters. Extensive experimental field emission data from amorphous carbon thin films, amorphous silicon thin films and other materials has been gathered. This data has been used to determine the mechanisms responsible for the observed electron emission. Preliminary computer simulations using appropriate values for the different material properties have exhibited emission mechanisms similar to those identified by experiment. (author)

  15. Organic photo detectors for an integrated thin-film spectrometer

    Science.gov (United States)

    Peters, Sabine; Sui, Yunwu; Glöckler, Felix; Lemmer, Uli; Gerken, Martina

    2007-09-01

    We introduce a thin-film spectrometer that is based on the superprism effect in photonic crystals. While the reliable fabrication of two and three dimensional photonic crystals is still a challenge, the realization of one-dimensional photonic crystals as thin-film stacks is a relatively easy and inexpensive approach. Additionally, dispersive thin-film stacks offer the possibility to custom-design the dispersion profile according to the application. The thin-film stack is designed such that light incident at an angle experiences a wavelength-dependent spatial beam shift at the output surface. We propose the monolithic integration of organic photo detectors to register the spatial beam position and thus determine the beam wavelength. This thin-film spectrometer has a size of approximately 5 mm2. We demonstrate that the output position of a laser beam is determined with a resolution of at least 20 μm by the fabricated organic photo detectors. Depending on the design of the thin-film filter the wavelength resolution of the proposed spectrometer is at least 1 nm. Possible applications for the proposed thin-film spectrometer are in the field of absorption spectroscopy, e.g., for gas analysis or biomedical applications.

  16. Thin film thickness measurements using Scanning White Light Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Maniscalco, B.; Kaminski, P.M.; Walls, J.M., E-mail: J.M.Walls@lboro.ac.uk

    2014-01-01

    Scanning White Light Interferometry is a well-established technique for providing accurate surface roughness measurements and three dimensional topographical images. Here we report on the use of a variant of Scanning White Light Interferometry called coherence correlation interferometry which is now capable of providing accurate thickness measurements from transparent and semi-transparent thin films with thickness below 1 μm. This capability will have many important applications which include measurements on optical coatings, displays, semiconductor devices, transparent conducting oxides and thin film photovoltaics. In this paper we report measurements of thin film thickness made using coherence correlation interferometry on a variety of materials including metal-oxides (Nb{sub 2}O{sub 5} and ZrO{sub 2}), a metal-nitride (SiN{sub x}:H), a carbon-nitride (SiC{sub x}N{sub y}:H) and indium tin oxide, a transparent conducting oxide. The measurements are compared with those obtained using spectroscopic ellipsometry and in all cases excellent correlation is obtained between the techniques. A key advantage of this capability is the combination of thin film thickness and surface roughness and other three-dimensional metrology measurements from the same sample area. - Highlights: • Capability to make thin film measurements with sub-nanometre accuracy • Measurements of thin film thickness made on metal-oxides, nitrides and carbon-nitrides • Excellent correlation with thickness measurements using spectroscopic ellipsometry • Thin film measurement and nanometrology from the same sample area.

  17. Optical properties of rubrene thin film prepared by thermal evaporation

    Institute of Scientific and Technical Information of China (English)

    陈亮; 邓金祥; 孔乐; 崔敏; 陈仁刚; 张紫佳

    2015-01-01

    Rubrene thin films are deposited on quartz substrates and silver nanoparticles (Ag NPs) films by the thermal evapo-ration technique. The optical properties of rubrene thin film are investigated in a spectral range of 190 nm–1600 nm. The analysis of the absorption coefficient (α) reveals direct allowed transition with a corresponding energy of 2.24 eV. The photoluminescence (PL) peak of the rubrene thin film is observed to be at 563 nm (2.21 eV). With the use of Ag NPs which are fabricated by radio-frequency (RF) magnetron sputtering on the quartz, the PL intensity is 8.5 times that of as-deposited rubrene thin film. It is attributed to the fact that the surface plasmon enhances the photoluminescence.

  18. Optical and Structural Properties of Ultra-thin Gold Films

    CERN Document Server

    Kossoy, Anna; Simakov, Denis; Leosson, Kristjan; Kéna-Cohen, Stéphane; Maier, Stefan A

    2014-01-01

    Realizing laterally continuous ultra-thin gold films on transparent substrates is a challenge of significant technological importance. In the present work, formation of ultra-thin gold films on fused silica is studied, demonstrating how suppression of island formation and reduction of plasmonic absorption can be achieved by treating substrates with (3-mercaptopropyl) trimethoxysilane prior to deposition. Void-free fi lms with deposition thickness as low as 5.4 nm are realized and remain structurally stable at room temperature. Based on detailed structural analysis of the fi lms by specular and diffuse X-ray reflectivity measurements, it is shown that optical transmission properties of continuous ultra-thin films can be accounted for using the bulk dielectric function of gold. However, it is important to take into account the non-abrupt transition zone between the metal and the surrounding dielectrics, which extends through several lattice constants for the laterally continuous ultra-thin films (film thickness...

  19. Nanomechanical behavior of (1 0 0) oriented titanium thin films

    Science.gov (United States)

    Vasu, Kuraganti; Ghanashyam Krishna, Mamidipudi; Padmanabhan, Kuppuswamy Anantha

    2014-03-01

    Titanium thin films were deposited on single crystal Si (3 1 1) and polycrystalline 316 LN nuclear grade stainless steel substrates by RF magnetron sputtering. X-ray diffraction revealed that, irrespective of substrate type, films exhibit preferential growth along the (1 0 0) plane. The microstructure of the films corresponds to the zone-I type in structure zone model on both substrates. The hardness and Young's modulus of the films were extracted from load-displacement curves. The maximum values of hardness and Young's modulus were 12 and 132 GPa respectively for 220 nm thin film on SS substrate. The electrical resistivity data revealed that the films are metallic in nature and the resistivity is lower in the case of the 220 nm thickness film, on both substrates. The observed changes in mechanical and electrical properties can be correlated with variations in the microstructure of Ti films.

  20. Fracture of nanoporous organosilicate thin films

    Science.gov (United States)

    Gage, David Maxwell

    Nanoporous organosilicate thin films are attractive candidates for a number of emerging technologies, ranging from biotechnology to optics and microelectronics. However, integration of these materials is challenged by their fragile nature and susceptibility to mechanical failure. Debonding and cohesive cracking of the organosilicate film are principal concerns that threaten the reliability and yield of device structures. Despite the intense interest in these materials, there is currently a need for greater understanding of the relationship between glass structure and thermomechanical integrity. The objective of this research was to investigate strategies for improving mechanical performance through variations in film chemistry, process conditions, and pore morphology. Several approaches to effecting improvements in elastic and fracture properties were examined in depth, including post-deposition curing, molecular reinforcement using hydrocarbon network groups, and manipulation of pore size and architecture. Detailed structural characterization was employed along with quantitative fracture mechanics based testing methods. It was shown that ultra-violet irradiation and electron bombardment post-deposition treatments can significantly impact glass structure in ways that cannot be achieved through thermal activation alone. Both techniques demonstrated high porogen removal efficiency and enhanced the glass matrix through increased network connectivity and local bond rearrangements. The increases in network connectivity were achieved predominantly through the replacement of terminal groups, particularly methyl and silanol groups, with Si-O network bonds. Nuclear magnetic resonance spectroscopy was shown to be a powerful and quantitative method for gaining new insight into the underlying cure reactions and mechanisms. It was demonstrated that curing leads to significant progressive enhancement of elastic modulus and adhesive fracture energies due to increased network bond

  1. Development of neutron diffuse scattering analysis code by thin film and multilayer film

    International Nuclear Information System (INIS)

    To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering

  2. Thin liquid film flow and heat transfer under spray impingement

    International Nuclear Information System (INIS)

    A mathematical model was derived to investigate thin liquid film flow under spray impingement. Based on predicted flow patterns, a heat transfer model was developed to investigate the heat transfer performance in the non-boiling regime of spray cooling. The film thickness predicted by the thin film flow model favourably compares with reported experimental results obtained at different measurement locations and nozzle inlet pressures. It is found that the film thickness is sensitive to droplet flux distribution but not the nozzle inlet pressure. The comparison of the heated surface temperature between the proposed heat transfer model and the published experimental data shows good agreement. - Highlights: ► Thin liquid film flow in spray cooling is theoretically studied. ► A thin liquid film flow model is derived to predict the thin film flow pattern under spray impingement. ► A heat transfer model is developed to predict the heat transfer performance in the non-boiling regime of spray cooling. ► Film thickness of the liquid film flow is sensitive to droplet flux distribution but not the nozzle inlet pressure. ► Droplet impingement cooling is the primary cooling mechanism in the non-boiling regime of spray cooling.

  3. Buckling of Thin Films in Nano-Scale

    Science.gov (United States)

    Wang, S.; Jia, H. K.; Sun, J.; Ren, X. N.; Li, L. A.

    2010-06-01

    Investigation of thin film buckling is important for life prediction of MEMS device which are damaged mainly by the delamination and buckling of thin films. In this paper the mechanical and thermal properties of compressed thin film titanium films with 150 nm thickness deposited on an organic glass substrate under mechanical and thermal loads were measured and characterized. In order to simulate the thin films which subjected to compound loads and the buckle modes the external uniaxial compression and thermal loading were subjected to the specimen by the symmetric loading device and the electrical film in this experiment. The temperature of the thin film deposited on substrate was measured using thermoelectric couple. The range of temperature accords with the temperature range of the MEMS. It is found that the size and number of the delamination and buckling of the film are depended upon the pre-fixed mechanical loading and thermal temperature. The thermal transient conduction and thermal stability of the film and substrate was studied with finite element method.

  4. Buckling of Thin Films in Nano-Scale

    Directory of Open Access Journals (Sweden)

    Li L.A.

    2010-06-01

    Full Text Available Investigation of thin film buckling is important for life prediction of MEMS device which are damaged mainly by the delamination and buckling of thin films. In this paper the mechanical and thermal properties of compressed thin film titanium films with 150 nm thickness deposited on an organic glass substrate under mechanical and thermal loads were measured and characterized. In order to simulate the thin films which subjected to compound loads and the buckle modes the external uniaxial compression and thermal loading were subjected to the specimen by the symmetric loading device and the electrical film in this experiment. The temperature of the thin film deposited on substrate was measured using thermoelectric couple. The range of temperature accords with the temperature range of the MEMS. It is found that the size and number of the delamination and buckling of the film are depended upon the pre-fixed mechanical loading and thermal temperature. The thermal transient conduction and thermal stability of the film and substrate was studied with finite element method.

  5. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films

    OpenAIRE

    Sun, Jie; Sun, Yingchun

    2007-01-01

    Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system pH value played an important role in this experiment. The growth rate is 12 nm/h at room temperature. Post-growth annealing not only densifies and purifies the films, but results in film crystallization a...

  6. Nonlinear absorption of ultrashort laser pulses in thin metal films

    OpenAIRE

    Manfredi, Giovanni; Hervieux, Paul-Antoine

    2005-01-01

    Self-consistent simulations of the ultrafast electron dynamics in thin metal films are performed. A regime of nonlinear oscillations is observed, which corresponds to ballistic electrons bouncing back and forth against the film surfaces. When an oscillatory laser field is applied to the film, the field energy is partially absorbed by the electron gas. Maximum absorption occurs when the period of the external field matches the period of the nonlinear oscillations, which, for sodium films, lies...

  7. Electro-optical Properties of Ultra-Thin Organic Films

    OpenAIRE

    Hodges, Ping Y.

    2001-01-01

    Electro-optical properties of thin film are of great interest owing to the perpetual demand for miniaturization and higher speed devices for communication, electronic, and biomedical applications. The thickness of polymer films developed for these applications has decreased dramatically making interfacial effects significant. It is well documented that, in submicron thickness range, both film/substrate & film/air interface are critical. In this study, we probe the dynamics of electro-optic...

  8. Nonlinear optical properties of Au/PVP composite thin films

    Institute of Scientific and Technical Information of China (English)

    Shen Hong; Cheng Bo-Lin; Lu Guo-Wei; Wang Wei-Tian; Guan Dong-Yi; Chen Zheng-Hao; Yang Guo-Zhen

    2005-01-01

    Colloidal Au and poly(vinylpyrrolidone) (PVP) composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of films.

  9. Quantum-well-induced ferromagnetism in thin films

    DEFF Research Database (Denmark)

    Niklasson, A.M.N.; Mirbt, S.; Skriver, Hans Lomholt;

    1997-01-01

    We have used a first-principles Green's-function technique to investigate the magnetic properties of thin films of Rh, Pd, and Pt deposited on a fee Ag (001) substrate. We find that the magnetic moment of the film is periodically suppressed and enhanced as a function of film thickness....... The phenomenon is explained in terms of quantum-well states moving through the Fermi level with increasing film thickness....

  10. Residual stress in spin-cast polyurethane thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hong; Zhang, Li, E-mail: lizhang@mae.cuhk.edu.hk [Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China); Chow Yuk Ho Technology Centre for Innovative Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China)

    2015-01-19

    Residual stress is inevitable during spin-casting. Herein, we report a straightforward method to evaluate the residual stress in as-cast polyurethane thin films using area shrinkage measurement of films in floating state, which shows that the residual stress is independent of radial location on the substrate and decreased with decreasing film thickness below a critical value. We demonstrate that the residual stress is developed due to the solvent evaporation after vitrification during spin-casting and the polymer chains in thin films may undergo vitrification at an increased concentration. The buildup of residual stress in spin-cast polymer films provides an insight into the size effects on the nature of polymer thin films.

  11. Electrochromic properties of nanocrystalline MoO3 thin films

    International Nuclear Information System (INIS)

    Electrochromic MoO3 thin films were prepared by a sol-gel spin-coating technique. The spin-coated films were initially amorphous; they were calcined, producing nanocrystalline MoO3 thin films. The effects of annealing temperatures ranging from 100 oC to 500 oC were investigated. The electrochemical and electrochromic properties of the films were measured by cyclic voltammetry and by in-situ optical transmittance techniques in 1 M LiClO4/propylene carbonate electrolyte. Experimental results showed that the transmittance of MoO3 thin films heat-treated at 350 oC varied from 80% to 35% at λ = 550 nm (ΔT = ∼ 45%) and from 86% to 21% at λ ≥ 700 nm (ΔT = ∼ 65%) after coloration. Films heat-treated at 350 deg. C exhibited the best electrochromic properties in the present study

  12. Thin-film organic photonics molecular layer deposition and applications

    CERN Document Server

    Yoshimura, Tetsuzo

    2011-01-01

    Among the many atomic/molecular assembling techniques used to develop artificial materials, molecular layer deposition (MLD) continues to receive special attention as the next-generation growth technique for organic thin-film materials used in photonics and electronics. Thin-Film Organic Photonics: Molecular Layer Deposition and Applications describes how photonic/electronic properties of thin films can be improved through MLD, which enables precise control of atomic and molecular arrangements to construct a wire network that achieves ""three-dimensional growth"". MLD facilitates dot-by-dot--o

  13. Preparation and superconductivity of iron selenide thin films

    OpenAIRE

    Han, Y.; Li, W. Y.; Cao, L. X.; S. Zhang; Xu, B; Zhao, B. R.

    2009-01-01

    FeSex (x = 0.80, 0.84, 0.88, 0.92) thin films were prepared on SrTiO3(001) (STO), (La,Sr)(Al,Ta)O3(001) (LSAT), and LaAlO3(001) (LAO) substrates by pulsed laser deposition method. All thin films show single-phase and c-axis oriented epitaxial growth, and are superconducting. Among them, the FeSe0.88 thin films show Tc, onset of 11.8 K and Tc, 0 of 3.4 K. The upper critical magnetic field is estimated to be 14.0 T.

  14. Angular magnetoresistance in semiconducting undoped amorphous carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sagar, Rizwan Ur Rehman; Saleemi, Awais Siddique; Zhang, Xiaozhong, E-mail: xzzhang@tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People' s Republic of China and Beijing National Center for Electron Microscopy, Beijing 100084 (China)

    2015-05-07

    Thin films of undoped amorphous carbon thin film were fabricated by using Chemical Vapor Deposition and their structure was investigated by using High Resolution Transmission Electron Microscopy and Raman Spectroscopy. Angular magnetoresistance (MR) has been observed for the first time in these undoped amorphous carbon thin films in temperature range of 2 ∼ 40 K. The maximum magnitude of angular MR was in the range of 9.5% ∼ 1.5% in 2 ∼ 40 K. The origin of this angular MR was also discussed.

  15. Double Laser for Depth Measurement of Thin Films of Ice.

    Science.gov (United States)

    Beltrán, Manuel Domingo; Molina, Ramón Luna; Aznar, Miguel Ángel Satorre; Moltó, Carmina Santonja; Verdú, Carlos Millán

    2015-01-01

    The use of thin films is extensive in both science and industry. We have created an experimental system that allows us to measure the thicknesses of thin films (with typical thicknesses of around 1 µm) in real time without the need for any prior knowledge or parameters. Using the proposed system, we can also measure the refractive index of the thin film material exactly under the same experimental conditions. We have also obtained interesting results with regard to structural changes in the solid substance with changing temperature and have observed the corresponding behavior of mixtures of substances. PMID:26426024

  16. Hydrogenation Effect on Mg/Co Multilayer Thin Films

    OpenAIRE

    M.K. Jangid; S.P. NEHRA, M.SINGH

    2010-01-01

    Multilayer Mg/Co thin films have been prepared using thermal evaporation method at pressure 10-5torr. Annealing of structure has been performed in atmospheric condition at 600 K constant temperature for one hour. Hydrogenation of annealed thin films has been performed by keeping these in hydrogenation cell at different hydrogen pressures for 30 min. The UV–VIS absorption spectra of thin films have been carried out at room temperature in the wavelength range of 300–800 nm. The optical band gap...

  17. The state of the art of thin-film photovoltaics

    International Nuclear Information System (INIS)

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future

  18. Light management in thin-film silicon solar cells

    OpenAIRE

    Isabella, O.

    2013-01-01

    Solar energy can fulfil mankind’s energy needs and secure a more balanced distribution of primary sources of energy. Wafer-based and thin-film silicon solar cells dominate todays’ photovoltaic market because silicon is a non-toxic and abundant material and high conversion efficiencies are achieved with silicon-based solar cells. To stay competitive with bulk crystalline silicon and other thin-film solar cell technologies, thin-film silicon solar cells have to achieve a conversion efficiency l...

  19. Copper zinc tin sulfide-based thin film solar cells

    CERN Document Server

    Ito, Kentaro

    2014-01-01

    Beginning with an overview and historical background of Copper Zinc Tin Sulphide (CZTS) technology, subsequent chapters cover properties of CZTS thin films, different preparation methods of CZTS thin films, a comparative study of CZTS and CIGS solar cell, computational approach, and future applications of CZTS thin film solar modules to both ground-mount and rooftop installation. The semiconducting compound (CZTS) is made up earth-abundant, low-cost and non-toxic elements, which make it an ideal candidate to replace Cu(In,Ga)Se2 (CIGS) and CdTe solar cells which face material scarcity and tox

  20. Organic nanostructured thin film devices and coatings for clean energy

    CERN Document Server

    Zhang, Sam

    2010-01-01

    Authored by leading experts from around the world, the three-volume Handbook of Nanostructured Thin Films and Coatings gives scientific researchers and product engineers a resource as dynamic and flexible as the field itself. The first two volumes cover the latest research and application of the mechanical and functional properties of thin films and coatings, while the third volume explores the cutting-edge organic nanostructured devices used to produce clean energy. This third volume, Organic Nanostructured Thin Film Devices and Coatings for Clean Energy, addresses various aspects of the proc

  1. Assembly and Applications of Carbon Nanotube Thin Films

    Institute of Scientific and Technical Information of China (English)

    Hongwei ZHU; Bingqing WEI

    2008-01-01

    The ultimate goal of current research on carbon nanotubes (CNTs) is to make breakthroughs that advance nanotechnological applications of bulk CNT materials. Especially, there has been growing interest in CNT thin films because of their unique and usually enhanced properties and tremendous potential as components for use in nano-electronic and nano-mechanical device applications or as structural elements in various devices. If a synthetic or a post processing method can produce high yield of nanotube thin films, these structures will provide tremendous potential for fundamental research on these devices. This review will address the synthesis, the post processing and the device applications of self-assembled nanotube thin films.

  2. Nanoscale phenomena in ferroelectric thin films

    Science.gov (United States)

    Ganpule, Chandan S.

    Ferroelectric materials are a subject of intense research as potential candidates for applications in non-volatile ferroelectric random access memories (FeRAM), piezoelectric actuators, infrared detectors, optical switches and as high dielectric constant materials for dynamic random access memories (DRAMs). With current trends in miniaturization, it becomes important that the fundamental aspects of scaling of ferroelectric and piezoelectric properties in these devices be studied thoroughly and their impact on the device reliability assessed. In keeping with this spirit of miniaturization, the dissertation has two broad themes: (a) Scaling of ferroelectric and piezoelectric properties and (b) The key reliability issue of retention loss. The thesis begins with a look at results on scaling studies of focused-ion-beam milled submicron ferroelectric capacitors using a variety of scanning probe characterization tools. The technique of piezoresponse microscopy, which is rapidly becoming an accepted form of domain imaging in ferroelectrics, has been used in this work for another very important application: providing reliable, repeatable and quantitative numbers for the electromechanical properties of submicron structures milled in ferroelectric films. This marriage of FIB and SPM based characterization of electromechanical and electrical properties has proven unbeatable in the last few years to characterize nanostructures qualitatively and quantitatively. The second half of this dissertation focuses on polarization relaxation in FeRAMs. In an attempt to understand the nanoscale origins of back-switching of ferroelectric domains, the time dependent relaxation of remnant polarization in epitaxial lead zirconate titanate (PbZr0.2Ti0.8O 3, PZT) ferroelectric thin films (used as a model system), containing a uniform 2-dimensional grid of 90° domains (c-axis in the plane of the film) has been examined using voltage modulated scanning force microscopy. A novel approach of

  3. Fluorescent thin gel films using organic dyes and pigments

    Science.gov (United States)

    Nakazumi, Hiroyuki; Takashi, Tarao; Taniguchi, Shin-ichi; Nanto, Hidehito

    1997-10-01

    New organic-inorganic fluorescent thin gel films included with laser dyes or fluorescent organic pigments have been prepared for display application. The florescent dyes (benzoxazolium, pyrromethene, and rhodamine dyes) and super-fine particles of fluorescent pigments (coumarin and perylene) were successfully incorporated into thin silicate gel films prepared from tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), and methoxysilane oligomer (MTSO) under acid catalyzed hydrolysis. The blue, green, and red luminescence were observed from these thin films (thickness: 100 - 400 nm), respectively. Fluorescence spectra, fluorescent quantum yield and lifetime of thin gel films are examined. Fluorescent peaks for most of dyes and pigments used in gel films were similar to those in solution, and fluorescent lifetime for dyes and pigments used in gel films were 2.9 - 4.5 ns. Photostability of fluorescent gel films is dependent on fluorescent organic dyes and pigments used and/or silicate gel matrixes. Coumarin and perylene pigments have higher fluorescent quantum yield in gel film prepared from MTSO. The large Stokes shift was observed in fluorescent gel film using coumarin and benzoxazolium dyes. The coumarin and perylene pigments are significantly photo- stable in gel film prepared from MTSO, and photodegradation of perylene red after irradiation of 500 W Xi-lamp for 30 min is below 20%.

  4. Process compilation methods for thin film devices

    Science.gov (United States)

    Zaman, Mohammed Hasanuz

    This doctoral thesis presents the development of a systematic method of automatic generation of fabrication processes (or process flows) for thin film devices starting from schematics of the device structures. This new top-down design methodology combines formal mathematical flow construction methods with a set of library-specific available resources to generate flows compatible with a particular laboratory. Because this methodology combines laboratory resource libraries with a logical description of thin film device structure and generates a set of sequential fabrication processing instructions, this procedure is referred to as process compilation, in analogy to the procedure used for compilation of computer programs. Basically, the method developed uses a partially ordered set (poset) representation of the final device structure which describes the order between its various components expressed in the form of a directed graph. Each of these components are essentially fabricated "one at a time" in a sequential fashion. If the directed graph is acyclic, the sequence in which these components are fabricated is determined from the poset linear extensions, and the component sequence is finally expanded into the corresponding process flow. This graph-theoretic process flow construction method is powerful enough to formally prove the existence and multiplicity of flows thus creating a design space {cal D} suitable for optimization. The cardinality Vert{cal D}Vert for a device with N components can be large with a worst case Vert{cal D}Vert≤(N-1)! yielding in general a combinatorial explosion of solutions. The number of solutions is hence controlled through a-priori estimates of Vert{cal D}Vert and condensation (i.e., reduction) of the device component graph. The mathematical method has been implemented in a set of algorithms that are parts of the software tool MISTIC (Michigan Synthesis Tools for Integrated Circuits). MISTIC is a planar process compiler that generates

  5. Soft Magnetic Multilayered Thin Films for HF Applications

    Science.gov (United States)

    Loizos, George; Giannopoulos, George; Serletis, Christos; Maity, Tuhin; Roy, Saibal; Lupu, Nicoleta; Kijima, Hanae; Yamaguchi, Masahiro; Niarchos, Dimitris

    Multilayered thin films from various soft magnetic materials were successfully prepared by magnetron sputtering in Ar atmosphere. The magnetic properties and microstructure were investigated. It is found that the films show good soft magnetic properties: magnetic coercivity of 1-10 Oe and saturation magnetization higher than 1T. The initial permeability of the films is greater than 300 and flattens up to 600 MHz. The multilayer thin film properties in combination with their easy, fast and reproducible fabrication indicate that they are potential candidates for high frequency applications.

  6. Chemical analysis of thin films at Sandia National Laboratories

    International Nuclear Information System (INIS)

    The characterization of thin films produced by chemical and physical vapor deposition requires special analytical techniques. When the average compositions of the films are required, dissolution of the thin films and measurement of the concentrations of the solubilized species is the appropriate analytical approach. In this report techniques for the wet chemical analysis of thin films of Si:Al, P2O5:SiO2, B2O3:SiO2, TiB/sub x/ and TaB/sub x/ are described. The analyses are complicated by the small total quantities of these analytes present in the films, the refractory characters of these analytes, and the possibility of interferences from the substrates on which the films are deposited. Etching conditions are described which dissolve the thin films without introducing interferences from the substrates. A chemical amplification technique and inductively coupled plasma atomic emission spectrometry are shown to provide the sensitivity required to measure the small total quantities (micrograms to milligrams) of analytes present. Also the chemical analysis data has been used to calibrate normal infrared absorption spectroscopy to give fast estimates of the phosphorus and/or boron dopant levels in thin SiO2 films

  7. Production of nickel oxide thin films by magnetron sputtering

    International Nuclear Information System (INIS)

    Discrepancies between short-circuit diffusion data derived from nickel oxide bicrystals and specimens produced by the oxidation of nickel has led to a requirement for thin film nickel oxide specimens of controlled microstructure and impurity level that can be produced independently of the oxidation process. RF magnetron sputtering of nickel oxide has been used to produce thin films intended for this application. The as-deposited films contain excess oxygen compared to stoichiometric nickel oxide and exhibit strong preferred orientation. Annealing in argon leads to oxygen deficient films. The reduction in porosity which accompanies the annealing leads to the formation of through-thickness cracks in the films. Subsequent oxygen tracer studies demonstrate that the cracks give rise to excessive oxygen transport through the films compared to that expected for thermally oxidised scales. The microstructural anomalies produced by the annealing process mean that the required microstructures were not achieved and these films are not useful analogues of thermal nickel oxide scales. (author)

  8. Structure and Microstructure of Ni-Mn-Ga thin films

    Directory of Open Access Journals (Sweden)

    A.Annadurai

    2013-04-01

    Full Text Available Ni-Mn-Ga thin films were dc magnetron sputter deposited onto well cleaned substrates of si(100 and glass in high pure argon atmosphere of pressure of 0.01 mbar using NiMnGa alloy targets prepared in ourlaboratory by vacuum induction melting technique. Pristine thin films were investigated. Crystal structure of the films was studied using x-ray diffraction (XRD technique. Microstructure of the films was investigated using scanning electron microscope (SEM. XRD reveals that the films on glass substrates are amorphous and films on si(100 substrates posses L21 structure. SEM microstructure shows that the films on si(100 are polycrystalline in pristine form.

  9. Light waves in thin films and integrated optics.

    Science.gov (United States)

    Tien, P K

    1971-11-01

    Integrated optics is a far-reaching attempt to apply thin-film technology to optical circuits and devices, and, by using methods of integrated circuitry, to achieve a better and more economical optical system. The specific topics discussed here are physics of light waves in thin films, materials and losses involved, methods of couplings light beam into and out of a thin film, and nonlinear interactions in waveguide structures. The purpose of this paper is to review in some detail the important development of this new and fascinating field, and to caution the reader that the technology involved is difficult because of the smallness and perfection demanded by thin-film optical devices.

  10. Investigation on guided wave dispersion characteristics for metal thin films

    International Nuclear Information System (INIS)

    In this study, we investigated the dispersion characteristics of guided waves in thin films. Dispersion curves are essential for understanding not only the behavior of ultrasonic waves, but also the mechanical properties of thin films. Matrix techniques are presented for modeling ultrasonic waves in multilayered structures before being used to calculate the dispersion curves for Al-steel and Al-composite specimens. When compared with the dispersion curves obtained using the commercial program (Disperse), the dispersion curves generated from the transfer matrix method show its validity. These developed methods are used to obtain dispersion curves for Al thin films deposited on a Si substrate. The resulting dispersion curves enable observation of both dispersive and non-dispersive behavior for the guided waves, depending on the thickness of the thin films.

  11. Rip-Stop Reinforced Thin Film Sun Shield Structure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — During a proposed Phase I and Phase II program, PSI will advance the TRL from 3 to 6 for the ripstop reinforcement of thin film membranes used for large deployable...

  12. Mechanism of spontaneous hole formation in thin polymeric films

    DEFF Research Database (Denmark)

    Yu, Kaijia; Rasmussen, Henrik K.; Román Marín, José Manuel;

    2012-01-01

    We show computationally that (molten) thin polymeric film containing nonequilibrium configurations originating from a solvent evaporation may develop holes spontaneously in the molten state, and that they appear delayed. Polymers above the glass transition temperature are liquids where the flow...

  13. Hydrogenation Effect on Mg/Co Multilayer Thin Films

    Directory of Open Access Journals (Sweden)

    M. K. JANGID

    2010-11-01

    Full Text Available Multilayer Mg/Co thin films have been prepared using thermal evaporation method at pressure 10-5torr. Annealing of structure has been performed in atmospheric condition at 600 K constant temperature for one hour. Hydrogenation of annealed thin films has been performed by keeping these in hydrogenation cell at different hydrogen pressures for 30 min. The UV–VIS absorption spectra of thin films have been carried out at room temperature in the wavelength range of 300–800 nm. The optical band gap was found to be increase and conductivity has been found to be decreased with hydrogen pressure. The relative resistivity varies nonlinearly with time and increases with hydrogen pressure. Raman spectra of these sample shows decreasing intensity of peaks with hydrogenation. These results suggested that multilayer Mg/Co thin films structures can be used for hydrogen storage as well as solar collector materials.

  14. Chalcogenide thin film materials for next generation data storage

    OpenAIRE

    Simpson, Robert E.

    2008-01-01

    Data can be stored in the form of amorphous and crystalline marks within a chalcogenide thin film. Commonly Ge. Therefore Ga:La:S:Cu shows potential as a future electrical phase change data storage material.

  15. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for Polycrystalline Thin-Film Research: Cadmium Telluride at the National Center for Photovoltaics.

  16. On-Chip Sensing of Thermoelectric Thin Film's Merit.

    Science.gov (United States)

    Xiao, Zhigang; Zhu, Xiaoshan

    2015-01-01

    Thermoelectric thin films have been widely explored for thermal-to-electrical energy conversion or solid-state cooling, because they can remove heat from integrated circuit (IC) chips or micro-electromechanical systems (MEMS) devices without involving any moving mechanical parts. In this paper, we report using silicon diode-based temperature sensors and specific thermoelectric devices to characterize the merit of thermoelectric thin films. The silicon diode temperature sensors and thermoelectric devices were fabricated using microfabrication techniques. Specifically, e-beam evaporation was used to grow the thermoelectric thin film of Sb2Te3 (100 nm thick). The Seebeck coefficient and the merit of the Sb2Te3 thin film were measured or determined. The fabrication of silicon diode temperature sensors and thermoelectric devices are compatible with the integrated circuit fabrication. PMID:26193272

  17. Broadband back grating design for thin film solar cells

    KAUST Repository

    Janjua, Bilal

    2013-01-01

    In this paper, design based on tapered circular grating structure was studied, to provide broadband enhancement in thin film amorphous silicon solar cells. In comparison to planar structure an absorption enhancement of ~ 7% was realized.

  18. Stress in Thin Films; Diffraction Elastic Constants and Grain Interaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Untextured bulk polycrystals usually possess macroscopically isotropic elastic properties whereas for most thin films transverse isotropy is expected, owing to the limited dimensionality. The usually applied models for the calculation of elastic constants of polycrystals from single crystal elastic constants (so-called grain interaction models) erroneously predict macroscopic isotropy for an (untextured) thin film. This paper presents a summary of recent work where it has been demonstrated for the first time by X-ray diffraction analysis of stresses in thin films that elastic grain interaction can lead to macroscopically elastically anisotropic behaviour (shown by non-linear sin2ψ plots). A new grain interaction model, predicting the macroscopically anisotropic behaviour of thin films, is proposed.

  19. Thermal surface wave technique for thin film thermal diffusivity measurement

    OpenAIRE

    Zhang, B.; Imhof, R.; Hartree, W.

    1994-01-01

    A new method of measuring thermal diffusivities of isolated thin films, using variable transverse displacement between focused, modulated optical excitation and radiometric detection, with measurements on metal and plastic foils, is presented.

  20. Enhancement of the Electrical Properties in BaTiO3/PbZr0.52Ti0.48O3 Ferroelectric Superlattices.

    Science.gov (United States)

    He, Bin; Wang, Zhanjie

    2016-03-01

    In this study, BaTiO3/Pb(Zr0.52Ti0.48)O3 (BTO/PZT) ferroelectric superlattices have been grown on the Nb-doped SrTiO3 (NSTO) single-crystal substrate by pulsed laser deposition, and their electrical properties were investigated in detail. The leakage current was reduced significantly in the BTO/PZT superlattices, and the conduction mechanism could be interpreted as the bulk-limited mechanism. In addition, a more symmetric hysteresis loop was observed in the BTO/PZT superlattices compared with the pure PZT and BTO films. The BTO/PZT superlattices with the modulation thickness of 9.8 nm showed remarkably improved dielectric properties with dielectric constant and loss of 684 and 0.02, respectively, measured at the frequency of 10 kHz. Based on these experimental results, it can be considered that the BTO/PZT interfaces play a very important role for the enhanced electrical properties of the BTO/PZT superlattices. PMID:26913563